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  • 1. Aaboud, M.
    et al.
    Jensen, Bengt
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ohm, Christian
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ripellino, Giulia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Sidebo, P. Edvin
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Zwalinski, L.
    CERN, Geneva, Switzerland..
    Dijet azimuthal correlations and conditional yields in pp and p plus Pb collisions ats root S-NN=5.02 TeV with the ATLAS detector2019In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 100, no 3, article id 034903Article in journal (Refereed)
    Abstract [en]

    This paper presents a measurement of forward-forward and forward-central dijet azimuthal angular correlations and conditional yields in proton-proton (pp) and proton-lead (p + Pb) collisions as a probe of the nuclear gluon density in regions where the fraction of the average momentum per nucleon carried by the parton entering the hard scattering is low. In these regions, gluon saturation can modify the rapidly increasing parton distribution function of the gluon. The analysis utilizes 25 pb(-1) of pp data and 360 mu b(-1) of p + Pb data, both at root S-NN = 5.02 TeV, collected in 2015 and 2016, respectively, with the ATLAS detector at the Large Hadron Collider. The measurement is performed in the center-of-mass frame of the nucleon-nucleon system in the rapidity range between -4.0 and 4.0 using the two highest transverse-momentum jets in each event, with the highest transverse-momentum jet restricted to the forward rapidity range. No significant broadening of azimuthal angular correlations is observed for forward-forward or forward-central dijets in p + Pb compared to pp collisions. For forward-forward jet pairs in the proton-going direction, the ratio of conditional yields in p + Pb collisions to those in pp collisions is suppressed by approximately 20%, with no significant dependence on the transverse momentum of the dijet system. No modification of conditional yields is observed for forward-central dijets.

  • 2.
    Aaboud, M.
    et al.
    Univ Mohamed Premier, Fac Sci, Oujda, Morocco.;LPTPM, Oujda, Morocco..
    Kastanas, Konstatinos A.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Lund-Jensen, Bengt
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ohm, Christian
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ripellino, Giulia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Sidebo, Edvin
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Zwalinski, L.
    CERN, Geneva, Switzerland..
    et al,
    Measurement of the suppression and azimuthal anisotropy of muons from heavy-flavor decays in Pb plus Pb collisions at root s(NN)=2.76 TeV with the ATLAS detector2018In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 98, no 4, article id 044905Article in journal (Refereed)
    Abstract [en]

    ATLAS measurements of the production of muons from heavy-flavor decays in root s(NN) = 2.76 TeV Pb+Pb collisions and root s = 2.76 TeV pp collisions at the LHC are presented. Integrated luminosities of 0.14 nb(-1) and 570 nb(-1) are used for the Pb+Pb and pp measurements, respectively, which are performed over the muon transverse momentum range 4 < pT < 14 GeV and for five Pb+Pb centrality intervals. Backgrounds arising from in-flight pion and kaon decays, hadronic showers, and misreconstructed muons are statistically removed using a template-fitting procedure. The heavy-flavor muon differential cross sections and per-event yields are measured in pp and Pb+Pb collisions, respectively. The nuclear modification factor R-AA obtained from these is observed to be independent of pT, within uncertainties, and to be less than unity, which indicates suppressed production of heavy-flavor muons in Pb+Pb collisions. For the 10% most central Pb+Pb events, the measured R-AA is approximately 0.35. The azimuthal modulation of the heavy-flavor muon yields is also measured and the associated Fourier coefficients v(n) for n = 2, 3, and 4 are given as a function of pT and centrality. They vary slowly with pT and show a systematic variation with centrality which is characteristic of other anisotropy measurements, such as that observed for inclusive hadrons. The measured R-AA and v(n) values are also compared with theoretical calculations.

  • 3. Aaboud, M.
    et al.
    Kastanas, Konstatinos A.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Lund-Jensen, Bengt
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ohm, Christian
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ripellino, Giulia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Sidebo, P. Edvin
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Zwalinski, L.
    et al.,
    Measurement of jet fragmentation in Pb plus Pb and pp collisions at root S-NN=5.02 TeV with the ATLAS detector2018In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 98, no 2, article id 024908Article in journal (Refereed)
    Abstract [en]

    This paper presents a measurement of jet fragmentation functions in 0.49 nb(-1) of Pb +Pb collisions and 25 pb(-1) of pp collisions at root S-NN = 5.02 TeV collected in 2015 with the ATLAS detector at the LHC. These measurements provide insight into the jet quenching process in the quark-gluon plasma created in the aftermath of ultrarelativistic collisions between two nuclei. The modifications to the jet fragmentation functions are quantified by dividing the measurements in Pb+Pb collisions by baseline measurements in pp collisions. This ratio is studied as a function of the transverse momentum of the jet, the jet rapidity, and the centrality of the collision. In both collision systems, the jet fragmentation functions are measured for jets with transverse momentum between 126 and 398 GeV and with an absolute value of jet rapidity less than 2.1. An enhancement of particles carrying a small fraction of the jet momentum is observed, which increases with centrality and with increasing jet transverse momentum. Yields of particles carrying a very large fraction of the jet momentum are also observed to be enhanced. Between these two enhancements of the fragmentation functions a suppression of particles carrying an intermediate fraction of the jet momentum is observed in Pb+Pb collisions. A small dependence of the modifications on jet rapidity is observed.

  • 4. Aaboud, M.
    et al.
    Lund-Jensen, Bengt
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Sidebo, P. Edvin
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Zwalinski, L.
    et al.,
    Femtoscopy with identified charged pions in proton-lead collisions at root s(NN)=5.02 TeV with ATLAS2017In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 96, no 6Article in journal (Refereed)
    Abstract [en]

    Bose-Einstein correlations between identified charged pions are measured for p+Pb collisions at root s(NN) = 5.02 TeV using data recorded by the ATLAS detector at the CERN Large Hadron Collider corresponding to a total integrated luminosity of 28 nb(-1). Pions are identified using ionization energy loss measured in the pixel detector. Two-particle correlation functions and the extracted source radii are presented as a function of collision centrality as well as the average transverse momentum (k(T)) and rapidity (y*(pi pi)) of the pair. Pairs are selected with a rapidity -2 < y*(pi pi) < 1 and with an average transverse momentum 0.1 < k(T) < 0.8 GeV. The effect of jet fragmentation on the two-particle correlation function is studied, and a method using opposite-charge pair data to constrain its contributions to the measured correlations is described. The measured source sizes are substantially larger in more central collisions and are observed to decrease with increasing pair k(T). A correlation of the radii with the local charged-particle density is demonstrated. The scaling of the extracted radii with the mean number of participating nucleons is also used to compare a selection of initial-geometry models. The cross term R-ol is measured as a function of rapidity, and a nonzero value is observed with 5.1 sigma combined significance for -1 < y*pi pi < 1 in the most central events.

  • 5.
    Aad, G.
    et al.
    Aix Marseille Univ, IN2P3, CNRS, CPPM, Marseille, France..
    Jensen, Bengt
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ohm, Christian
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ripellino, Giulia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Shope, David R.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Zwalinski, L.
    CERN, Geneva, Switzerland..
    Exclusive dimuon production in ultraperipheral Pb plus Pb collisions at root S-NN=5.02 TeV with ATLAS2021In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 104, no 2, article id 024906Article in journal (Refereed)
    Abstract [en]

    Exclusive dimuon production in ultraperipheral collisions (UPC), resulting from photon-photon interactions in the strong electromagnetic fields of colliding high-energy lead nuclei, PbPb(gamma gamma) -> mu(+) mu(-) (Pb-(*Pb-)(()*())), is studied using L-int = 0.48 nb(-1) of root S-NN = 5.02 TeV lead-lead collision data at the LHC with the ATLAS detector. Dimuon pairs are measured in the fiducial region p(T,mu) > 4 GeV, vertical bar eta(mu)vertical bar < 2.4, invariant m(mu mu) > 10 GeV, and p(T,mu mu) <2 GeV. The primary background from single-dissociative processes is extracted from the data using a template fitting technique. Differential cross sections are presented as a function of m(mu mu), absolute pair rapidity (vertical bar y(mu mu)vertical bar), scattering angle in the dimuon rest frame (vertical bar cos v*(mu mu)vertical bar), and the colliding photon energies. The total cross section of the UPC gamma gamma -> mu(+) mu(-) process in the fiducial volume is measured to be sigma(mu mu)(fid) = 34.1 +0.3(stat.)+0.7(syst.) mu b. Generally good agreement is found with calculations from STARlight, which incorporate the leading-order Breit-Wheeler process with no final-state effects, albeit differences between the measurements and theoretical expectations are observed. In particular, the measured cross sections at larger vertical bar y(mu mu)vertical bar are found to be about 10-20% larger in data than in the calculations, suggesting the presence of larger fluxes of photons in the initial state. Modification of the dimuon cross sections in the presence of forward and/or backward neutron production is also studied and is found to be associated with a harder incoming photon spectrum, consistent with expectations.

  • 6.
    Aad, G.
    et al.
    Aix Marseille Univ, IN2P3, CNRS, CPPM, Marseille, France..
    Jensen, Bengt
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ohm, Christian
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ripellino, Giulia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Sidebo, P. Edvin
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Zwalinski, L.
    CERN, Geneva, Switzerland..
    et al.,
    Measurement of angular and momentum distributions of charged particles within and around jets in Pb plus Pb and pp collisions at root s(NN)=5.02 TeV with the ATLAS detector2019In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 100, no 6, article id 064901Article in journal (Refereed)
    Abstract [en]

    Studies of the fragmentation of jets into charged particles in heavy-ion collisions can provide information about the mechanism of jet quenching by the hot and dense QCD matter created in such collisions, the quark-gluon plasma. This paper presents a measurement of the angular distribution of charged particles around the jet axis in root s(NN) = 5.02 TeV Pb + Pb and pp collisions, using the ATLAS detector at the LHC. The Pb + Pb and pp data sets have integrated luminosities of 0.49 nb(-1) and 25 pb(-1), respectively. The measurement is performed for jets reconstructed with the anti-k(t) algorithm with radius parameter R = 0.4 and is extended to an angular distance of r = 0.8 from the jet axis. Results are presented as a function of Pb + Pb collision centrality and distance from the jet axis for charged particles with transverse momenta in the 1- to 63-GeV range, matched to jets with transverse momenta in the 126- to 316-GeV range and an absolute value of jet rapidity of less than 1.7. Modifications to the measured distributions are quantified by taking a ratio to the measurements in pp collisions. Yields of charged particles with transverse momenta below 4 GeV are observed to be increasingly enhanced as a function of angular distance from the jet axis, reaching a maximum at r = 0.6. Charged particles with transverse momenta above 4 GeV have an enhanced yield in Pb + Pb collisions in the jet core for angular distances up to r = 0.05 from the jet axis, with a suppression at larger distances.

  • 7.
    Aad, G.
    et al.
    CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille, France.
    Leopold, Alexander
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Lundberg, Olof
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Lund-Jensen, Bengt
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ohm, Christian
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ripellino, Giulia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Shaheen, Rabia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Shope, David R.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Zwalinski, L.
    CERN, Geneva, Switzerland.
    et al.,
    Correlations between flow and transverse momentum in Xe + Xe and Pb + Pb collisions at the LHC with the ATLAS detector: A probe of the heavy-ion initial state and nuclear deformation2023In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 107, no 5, article id e054910Article in journal (Refereed)
    Abstract [en]

    The correlations between flow harmonics vn for n = 2, 3, and 4 and mean transverse momentum [pT] in 129Xe + 129Xe and 208Pb + 208Pb collisions at √s = 5.44 and 5.02 TeV, respectively, are measured using charged particles with the ATLAS detector. The correlations are potentially sensitive to the shape and size of the initial geometry, nuclear deformation, and initial momentum anisotropy. The effects from nonflow and centrality fluctuations are minimized, respectively, via a subevent cumulant method and an event-activity selection based on particle production at very forward rapidity. The vn-[pT] correlations show strong dependencies on centrality, harmonic number n, pT, and pseudorapidity range. Current models qualitatively describe the overall centrality- and system-dependent trends but fail to quantitatively reproduce all features of the data. In central collisions, where models generally show good agreement, the v2-[pT] correlations are sensitive to the triaxiality of the quadruple deformation. Comparison of the model with the Pb + Pb and Xe + Xe data confirms that the 129Xe nucleus is a highly deformed triaxial ellipsoid that has neither a prolate nor oblate shape. This provides strong evidence for a triaxial deformation of the 129Xe nucleus from high-energy heavy-ion collisions.

  • 8.
    Aad, G.
    et al.
    Aix Marseille Univ, CPPM, CNRS IN2P3, Marseille, France..
    Leopold, Alexander
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Lundberg, Olof
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Lund-Jensen, Bengt
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ohm, Christian
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ripellino, Giulia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Shaheen, Rabia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Shope, David R.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Zwalinski, L.
    CERN, Geneva, Switzerland..
    et al.,
    Measurements of azimuthal anisotropies of jet production in Pb collisions at root(NN)-N-s=5.02 TeV with the ATLAS detector2022In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 105, no 6, article id 064903Article in journal (Refereed)
    Abstract [en]

    The azimuthal variation of jet yields in heavy-ion collisions provides information about the path-length dependence of the energy loss experienced by partons passing through the hot, dense nuclear matter known as the quark-gluon plasma. This paper presents the azimuthal anisotropy coefficients v(2), v(3), and v(4) measured for jets in Pb + Pb collisions at root(NN)-N-s =5.02 TeV using the ATLAS detector at the LHC. The measurement uses data collected in 2015 and 2018, corresponding to an integrated luminosity of 2.2 nb(-1). The v(n) values are measured as a function of the transverse momentum of the jets between 71 and 398 GeV and the event centrality. A nonzero value of v(2) is observed in all but the most central collisions. The value of v(2) is largest for jets with lower transverse momentum, with values up to 0.05 in mid-central collisions. A smaller, nonzero value of v(3) of approximately 0.01 is measured with no significant dependence on jet p(T) or centrality, suggesting that fluctuations in the initial state play a small but distinct role in jet energy loss. No significant deviation of v(4) from zero is observed in the measured kinematic region.

  • 9.
    Aad, G.
    et al.
    CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille, France.
    Leopold, Alexander
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Lundberg, Olof
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Lund-Jensen, Bengt
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ohm, Christian
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ripellino, Giulia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Shaheen, Rabia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Shope, David R.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Zwalinski, L.
    CERN, Geneva, Switzerland.
    et al.,
    Production of ϒ(nS) mesons in Pb + Pb and pp collisions at 5.02 TeV2023In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 107, no 5, article id e054912Article in journal (Refereed)
    Abstract [en]

    A measurement of the production of vector bottomonium states, ϒ(1S), ϒ(2S), and ϒ(3S), in Pb + Pb and pp collisions at a center-of-mass energy per nucleon pair of 5.02 TeV is presented. The data correspond to integrated luminosities of 1.38 nb-1 of Pb + Pb data collected in 2018, 0.44 nb-1 of Pb + Pb data collected in 2015, and 0.26 fb-1 of pp data collected in 2017 by the ATLAS detector at the Large Hadron Collider. The measurements are performed in the dimuon decay channel for transverse momentum pμμT < 30 GeV, absolute rapidity |yμμ| < 1.5, and Pb + Pb event centrality 0-80%. The production rates of the three bottomonium states in Pb + Pb collisions are compared with those in pp collisions to extract the nuclear modification factors as functions of event centrality, pμμT, and |yμμ|. In addition, the suppression of the excited states relative to the ground state is studied. The results are compared with theoretical model calculations.

  • 10.
    Aad, G.
    et al.
    CPPM, Aix Marseille Université, CNRS-IN2P3, Marseille; France.
    Lund-Jensen, Bengt
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ohm, Christian
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ripellino, Giulia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Shope, David R.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Zwalinski, L.
    The CERN, Geneva; Switzerland.
    et al.,
    Measurements of the suppression and correlations of dijets in Pb+Pb collisions atsNN = 5.02 TeV2023In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 107, no 5, article id 054908Article in journal (Refereed)
    Abstract [en]

    Studies of the correlations of the two highest transverse momentum (leading) jets in individual Pb+Pb collision events can provide information about the mechanism of jet quenching by the hot and dense matter created in such collisions. In Pb+Pb and pp collisions at√sNN = 5.02 TeV, measurements of the leading dijet transverse momentum (pT) correlations are presented. Additionally, measurements in Pb+Pb collisions of the dijet pair nuclear modification factors projected along leading and subleading jet pT are made. The measurements are performed using the ATLAS detector at the LHC with 260 pb−1 of pp data collected in 2017 and 2.2 nb−1 of Pb+Pb data collected in 2015 and 2018. An unfolding procedure is applied to the two-dimensional leading and subleading jet pT distributions to account for experimental effects in the measurement of both jets. Results are provided for dijets with leading jet pT greater than 100 GeV. Measurements of the dijet-yield-normalized xJ distributions in Pb+Pb collisions show an increased fraction of imbalanced jets compared to pp collisions; these measurements are in agreement with previous measurements of the same quantity at 2.76 TeV in the overlapping kinematic range. Measurements of the absolutely normalized dijet rate in Pb+Pb and pp collisions are also presented, and show that balanced dijets are significantly more suppressed than imbalanced dijets in Pb+Pb collisions. It is observed in the measurements of the pair nuclear modification factors that the subleading jets are significantly suppressed relative to leading jets with pT between 100 and 316 GeV for all centralities in Pb+Pb collisions.

  • 11. Aad, G.
    et al.
    Lund-Jensen, Bengt
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ohm, Christian
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ripellino, Giulia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Shope, David R.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Zwalinski, L.
    et.al,
    Two-particle azimuthal correlations in photonuclear ultraperipheral Pb plus Pb collisions at 5.02 TeV with ATLAS2021In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 104, no 1, article id 014903Article in journal (Refereed)
    Abstract [en]

    Two-particle long-range azimuthal correlations are measured in photonuclear collisions using 1.7 nb(-1) of 5.02 TeV Pb+Pb collision data collected by the ATLAS experiment at the CERN Large Hadron Collider. Candidate events are selected using a dedicated high-multiplicity photonuclear event trigger, a combination of information from the zero-degree calorimeters and forward calorimeters, and from pseudorapidity gaps constructed using calorimeter energy clusters and charged-particle tracks. Distributions of event properties are compared between data and Monte Carlo simulations of photonuclear processes. Two-particle correlation functions are formed using charged-particle tracks in the selected events, and a template-fitting method is employed to subtract the nonflow contribution to the correlation. Significant nonzero values of the second-and third-order flow coefficients are observed and presented as a function of charged-particle multiplicity and transverse momentum. The results are compared with flow coefficients obtained in proton-proton and proton-lead collisions in similar multiplicity ranges, and with theoretical expectations. The unique initial conditions present in this measurement provide a new way to probe the origin of the collective signatures previously observed only in hadronic collisions.

  • 12.
    Aad, G.
    et al.
    CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille; France.
    Lund-Jensen, Bengt
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ohm, Christian
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ripellino, Giulia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Sidebo, P. Edvin
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Zwalinski, L.
    CERN, Geneva; Switzerland.
    et al.,
    Measurement of muon pairs produced via γγ scattering in nonultraperipheral Pb + Pb collisions at √sNN = 5.02 TeV with the ATLAS detector2023In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 107, no 5, article id 054907Article in journal (Refereed)
    Abstract [en]

    Results of a measurement of dimuon photoproduction in nonultraperipheral Pb + Pb collisions at √sNN = 5.02 TeV are presented. Themeasurement uses ATLAS data from the 2015 and 2018 Pb + Pb data-taking periods at the LHC with an integrated luminosity of 1.94 nb.1. The γγ → μ+ μ- pairs are identified via selections on pair momentum asymmetry and acoplanarity. Differential cross sections for dimuon production are measured in different centrality, average muon momentum, and pair rapidity intervals as functions of acoplanarity and k⊥, the transverse momentum kick of one muon relative to the other. Measurements are also made as a function of the rapidity separation of the muons and the angle of the muon pair relative to the second-order event plane to test whether magnetic fields generated in the quark-gluon plasma affect the measured muons. A prior observation of a centrality-dependent broadening of the acoplanarity distribution is confirmed. Furthermore, the improved precision of the measurement reveals a depletion in the number of pairs having small acoplanarity or k⊥ values in more central collisions. The acoplanarity distributions in a given centrality interval are observed to vary with the mean pT of the muons in the pair, but the k⊥ distributions do not. Comparisons with recent theoretical predictions are made. The predicted trends associated with effects of magnetic fields on the dimuons are not observed.

  • 13.
    Aad, G.
    et al.
    Aix Marseille Univ, IN2P3, CNRS, CPPM, Marseille, France..
    Lund-Jensen, Bengt
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ohm, Christian
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ripellino, Giulia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Sidebo, P. Edvin
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Zwalinski, L.
    CERN, Geneva, Switzerland..
    et al.,
    Measurement of the azimuthal anisotropy of charged-particle production in Xe plus Xe collisions at root S-NN=5.44 TeV with the ATLAS detector2020In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 101, no 2, article id 024906Article in journal (Refereed)
    Abstract [en]

    This paper describes the measurements of flow harmonics v(2)-v(6) in 3 mu b(-1) of Xe Xe collisions at root S-NN = 5.44 TeV performed using the ATLAS detector at the Large Hadron Collider (LHC). Measurements of the centrality, multiplicity, and p(T) dependence of the v(n) obtained using two-particle correlations and the scalar product technique are presented. The measurements are also performed using a template-fit procedure, which was developed to remove nonflow correlations in small collision systems. This nonflow removal is shown to have a significant influence on the measured v(n) at high p(T), especially in peripheral events. Comparisons of the measured v(n) with measurements in Pb + Pb collisions and p + Pb collisions at root S-NN = 5.02 TeV are also presented. The v(n) values in Xe + Xe collisions are observed to be larger than those in Pb + Pb collisions for n = 2, 3, and 4 in the most central events. However, with decreasing centrality or increasing harmonic order n, the v(n) values in Xe + Xe collisions become smaller than those in Pb + Pb collisions. The v(n) in Xe + Xe and Pb + Pb collisions are also compared as a function of the mean number of participating nucleons, < N-part >, and the measured charged-particle multiplicity in the detector. The v(3) values in Xe + Xe and Pb + Pb collisions are observed to be similar at the same < N-part > or multiplicity, but the other harmonics are significantly different. The ratios of the measured v(n) in Xe + Xe and Pb + Pb collisions, as a function of centrality, are also compared to theoretical calculations.

  • 14.
    Al-Adili, A.
    et al.
    Uppsala Univ, Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden..
    Tarrio, D.
    Uppsala Univ, Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden..
    Jansson, K.
    Uppsala Univ, Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden..
    Rakopoulos, V
    Uppsala Univ, Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden..
    Solders, A.
    Uppsala Univ, Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden..
    Pomp, S.
    Uppsala Univ, Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden..
    Göök, Alf
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. European Commiss, DG Joint Res Ctr, Directorate G Nucl Safety & Secur, Unit G-2 SN3S, B-2440 Geel, Belgium.
    Hambsch, F-J
    European Commiss, DG Joint Res Ctr, Directorate G Nucl Safety & Secur, Unit G-2 SN3S, B-2440 Geel, Belgium..
    Oberstedt, S.
    European Commiss, DG Joint Res Ctr, Directorate G Nucl Safety & Secur, Unit G-2 SN3S, B-2440 Geel, Belgium..
    Vidali, M.
    European Commiss, DG Joint Res Ctr, Directorate G Nucl Safety & Secur, Unit G-2 SN3S, B-2440 Geel, Belgium..
    Prompt fission neutron yields in thermal fission of U-235 and spontaneous fission of Cf-2522020In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 102, no 6, article id 064610Article in journal (Refereed)
    Abstract [en]

    Background: The sharing of excitation energy between the fission fragments is one of the key issues in studying nuclear fission. One way to address this is by studying prompt-fission neutron multiplicities as a function of other fission observables such as the mass, (nu) over bar (A). These are vital benchmark data for both fission and nuclear deexcitation models, putting constrains on the fragment excitation energy and hence on the competing prompt neutron/gamma-ray emission. Despite numerous detailed studies, recent measurements done at JRC-Geel with the SCINTIA array in the epithermal region show surprisingly strong discrepancies to earlier thermal fission data and the Wahl systematics. Purpose: The purpose was to perform measurements of the prompt-fission neutron multiplicity, as a function of fragment mass and total kinetic energy (TKE), in U-235(n(th), f) and Cf-252(sf), to verify and extend the SCINTIA results. Another goal was to validate the analysis methods, and prepare for planned investigations at excitation energies up to 5.5 MeV. Methods: The experiments were conducted at the former 7 MV Van de Graaff facility in JRC-Geel, using a Twin Frisch-Grid Ionization Chamber and two liquid scintillation detectors. A neutron beam with an average energy of 0.5 MeV was produced via the Li-7(p,n) reaction. The neutrons were thermalized by a 12 cm thick block of paraffin. Digital data acquisition systems were utilized. Comprehensive simulations were performed to verify the methodology and to investigate the role of the mass and energy resolution on measured (nu) over bar (A) and (nu) over bar (TKE) values. The simulation results also revealed that the partial derivative(nu) over bar/partial derivative A and partial derivative(TKE) over bar/partial derivative(nu) over bar are affected by the mass and energy resolution. However, the effect is small for the estimated resolutions of this work. Detailed Fluka simulations were performed to calculate the fraction of thermal neutron-induced fission, which was estimated to be about 98%. Results: The experimental results on (nu) over bar (A) are in good agreement with earlier data for Cf-252(sf). For U-235(n(th), f), the (nu) over bar (A) data is very similar to the data obtained with SCINTIA, and therefore we verify these disclosed discrepancies to earlier thermal data and to the Wahl evaluation. The experimental results on (nu) over bar (TKE) are also in agreement with the data at epithermal energies. For Cf-252(sf) a slope value of partial derivative(TKE) over bar/partial derivative(nu) over bar = (-12.9 f 0.2) MeV/n was obtained. For U-235(n(th), f) the value is (-12.0 +/- 0.1) MeV/n. Finally, the neutron spectrum in the center-of-mass system was derived and plotted as a function of fragment mass. Conclusions: This work clearly proves the lack of accurate correlation between fission fragment and neutron data even in the best-studied reactions. The new results highlight the need of a new evaluation of the prompt-fission multiplicity for U-225(n(th), f).

  • 15.
    Amaro, Mário B.
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Karlsson, Daniel
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Multilinear analysis of the systematics of proton radioactivity2023In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 108, no 5, article id 054311Article in journal (Refereed)
    Abstract [en]

    It is shown that the proton formation probabilities, extracted from experimental decay half-lives, can be well reproduced by a simple multilinear formula with only three parameters. The parameters obtained by considering the standard root mean square deviation and the mini-max criteria are very similar to each other. In addition, we applied Bayesian analysis to study the uncertainties of the parameters and the model predictions. In this way we explain the systematics of proton decay half-lives. The multilinearity of the model also provides a way to classify the relative hindrance of different proton decays. All the recent experimental data agree very well with the model prediction. Our Bayesian analysis suggests that those new data do help constrain the uncertainty of the model parameters.

  • 16. Auranen, K.
    et al.
    Uusitalo, J.
    Juutinen, S.
    Badran, H.
    Bisso, F. Defranchi
    Cox, D.
    Grahn, T.
    Greenlees, P. T.
    Herzan, A.
    Jakobsson, Ulrika
    KTH, School of Engineering Sciences (SCI), Physics. University of Helsinki, Finland.
    Julin, R.
    Konki, J.
    Leino, M.
    Lightfoot, A.
    Mallaburn, M. J.
    Neuvonen, O.
    Pakarinen, J.
    Papadakis, P.
    Partanen, J.
    Rahkila, P.
    Sandzelius, M.
    Saren, J.
    Scholey, C.
    Sorri, J.
    Stolze, S.
    Wang, Y. K.
    Prompt and delayed spectroscopy of At-203: Observation of a shears band and a 29/2(+) isomeric state2018In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 97, no 2, article id 024301Article in journal (Refereed)
    Abstract [en]

    Using fusion-evaporation reactions, a gas-filled recoil separator, recoil-gating technique and recoil-isomer decay tagging technique we have extended the level scheme of At-203 (N = 118) significantly. We have observed an isomeric [tau = 14.1(3) mu s] state with a spin and parity of 29/2(+). The isomeric state is suggested to originate from the pi(h(9/2)) circle times |Po-202; 11(-)> coupling, and it is depopulated through 286 keV E2 and 366 keV E3 transitions. In addition, we have observed a cascade of magnetic-dipole transitions which is suggested to be generated by the shears mechanism.

  • 17. Auranen, K.
    et al.
    Uusitalo, J.
    Juutinen, S.
    Badran, H.
    Bisso, F. Defranchi
    Cox, D.
    Grahn, T.
    Greenlees, P. T.
    Herzan, A.
    Jakobsson, Ulrika
    KTH, School of Engineering Sciences (SCI), Physics.
    Julin, R.
    Konki, J.
    Leino, M.
    Lightfoot, A.
    Mallaburn, M.
    Neuvonen, O.
    Pakarinen, J.
    Papadakis, P.
    Partanen, J.
    Rahkila, P.
    Sandzelius, M.
    Saren, J.
    Scholey, C.
    Sorri, J.
    Stolze, S.
    Experimental study of isomeric intruder 1/2(+) states in At-197,At-2032017In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 95, no 4, article id 044311Article in journal (Refereed)
    Abstract [en]

    A newly observed isomeric intruder 1/2(+) state [T-1/2 = 3.5( 6) ms] is identified in At-203 using a gas-filled recoil separator and fusion-evaporation reactions. The isomer is depopulated through a cascade of E3 and mixed M1/E2 transitions to the 9/2(-) ground state, and it is suggested to originate from the pi(s(1/2))(-1) configuration. In addition, the structures above the 1/2(+) state in At-203 and At-197 are studied using in-beam gamma-ray spectroscopy, recoil-decay tagging, and recoil-isomer decay tagging methods. The 1/2(+) state is fed from 3/2(+) and 5/2(+) states, and the origin of these states are discussed.

  • 18. Badran, H.
    et al.
    Scholey, C.
    Uusitalo, J.
    Auranen, K.
    Grahn, T.
    Greenlees, P. T.
    Herzan, A.
    Jakobsson, Ulrika
    KTH, School of Engineering Sciences (SCI), Physics.
    Julin, R.
    Juutinen, S.
    Konki, J.
    Leino, M.
    Mallaburn, M. J.
    Pakarinen, J.
    Papadakis, P.
    Partanen, J.
    Peura, P.
    Rahkila, P.
    Sandzelius, M.
    Saren, J.
    Sorri, J.
    Stolze, S.
    Decay spectroscopy of Pb-179(82)97 and evidence for a 9/2(-) intruder state in Tl-179(81)982017In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 96, no 6, article id 064314Article in journal (Refereed)
    Abstract [en]

    The very neutron-deficient isobars Pb-179 and Tl-179 have been produced using the fusion-evaporation reactions Pd-104(Kr-78,xpyn), where x <= 1 and y >= 2. The gas-filled separator RITU was employed to transport and separate the recoiling nuclei of interest from the scattered beam and unwanted products. The GREAT spectrometer was used to study the decay properties through alpha-alpha and alpha-gamma correlations, which has allowed the ground state of Pb-179 to be assigned as I-pi = 9/2(-). The decay of Pb-179 was measured to have an alpha-particle energy and half-life of E-alpha = 7348(5) keV and t(1/2) = 2.7(2) ms, respectively. A search for a nu i(13/2) state in Pb-179 was performed, but only a limit of excitation energy and half-life was obtained. In Tl-179 a t(1/2) = 114(-10)(+18) ns isomeric state, likely at an excitation energy of 904.5(9) keV, was identified and is tentatively assigned to be a 9/2(-) proton intruder state.

  • 19.
    Bhagwat, Ameeya
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. UM-DAE Centre for Excellence in Basic Sciences, India.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cluster decay in the superallowed alpha decay region2017In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 96, no 3, article id 031302Article in journal (Refereed)
    Abstract [en]

    The emissions of a particles and protons are the dominant decay channels in the neutron-deficient nuclei corresponding to the sdg major shell. The possibility of cluster emission is explored here. It is shown that the cluster decay mode has a small yet sizable branching ratio.

  • 20.
    Biswas, S.
    et al.
    CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France..
    Lemasson, A.
    CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France..
    Rejmund, M.
    CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France..
    Navin, A.
    CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France..
    Kim, Y. H.
    CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France.;Inst Laue Langevin, F-38042 Grenoble, France..
    Michelagnoli, C.
    CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France.;Inst Laue Langevin, F-38042 Grenoble, France..
    Stefan, I
    Univ Paris Saclay, Univ Paris Sud, Inst Phys Nucl, IN2P3,CNRS, F-91406 Orsay, France..
    Banik, R.
    Variable Energy Cyclotron Ctr, 1-AF Bidhan Nagar, Kolkata 700064, India.;Homi Bhabha Natl Inst, Training Sch Complex, Mumbai 400094, Maharashtra, India..
    Bednarczyk, P.
    Inst Nucl Phys PAN, Krakow, Poland..
    Bhattacharya, S.
    Variable Energy Cyclotron Ctr, 1-AF Bidhan Nagar, Kolkata 700064, India.;Homi Bhabha Natl Inst, Training Sch Complex, Mumbai 400094, Maharashtra, India..
    Bhattacharyya, S.
    Variable Energy Cyclotron Ctr, 1-AF Bidhan Nagar, Kolkata 700064, India.;Homi Bhabha Natl Inst, Training Sch Complex, Mumbai 400094, Maharashtra, India..
    Clement, E.
    CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France..
    Crawford, H. L.
    Lawrence Berkeley Natl Lab, Nucl Sci Div, Berkeley, CA 94720 USA..
    de France, G.
    CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France..
    Fallon, P.
    Lawrence Berkeley Natl Lab, Nucl Sci Div, Berkeley, CA 94720 USA..
    Fremont, G.
    CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France..
    Goupil, J.
    CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France..
    Jacquot, B.
    CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France..
    Li, H. J.
    CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France..
    Ljungvall, J.
    Univ Paris Saclay, Univ Paris Sud, CSNSM, CNRS,IN2P3, F-91405 Orsay, France..
    Maj, A.
    Inst Nucl Phys PAN, Krakow, Poland..
    Menager, A.
    CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France..
    More, V
    CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France..
    Palit, R.
    Tata Inst Fundamental Res, Dept Nucl & Atom Phys, Mumbai 400005, Maharashtra, India..
    Perez-Vidal, R. M.
    Univ Valencia, CSIC, Inst Fis Corpuscular, E-46980 Valencia, Spain..
    Ropert, J.
    CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France..
    Barrientos, D.
    CERN, CH-1211 Geneva 23, Switzerland..
    Benzoni, G.
    Ist Nazl Fis Nucl, Sez Milano, Milan, Italy..
    Birkenbach, B.
    Univ Cologne, Inst Kernphys, Zulpicher Str 77, D-50937 Cologne, Germany..
    Boston, A. J.
    Univ Liverpool, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England..
    Boston, H. C.
    Univ Liverpool, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England..
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Collado, J.
    Univ Valencia, Dept Ingn Elect, Valencia, Spain..
    Cullen, D. M.
    Univ Manchester, Schuster Lab, Nucl Phys Grp, Manchester M13 9PL, Lancs, England..
    Desesquelles, P.
    Univ Paris Saclay, Univ Paris Sud, CSNSM, CNRS,IN2P3, F-91405 Orsay, France..
    Domingo-Pardo, C.
    Univ Valencia, CSIC, Inst Fis Corpuscular, E-46980 Valencia, Spain..
    Dudouet, J.
    Univ Paris Saclay, Univ Paris Sud, CSNSM, CNRS,IN2P3, F-91405 Orsay, France.;Univ Lyon 1, Univ Lyon, CNRS, IN2P3,UMR5822,IPNL, 4 Rue Enrico Fermi, F-69622 Villeurbanne, France..
    Eberth, J.
    Univ Cologne, Inst Kernphys, Zulpicher Str 77, D-50937 Cologne, Germany..
    Gonzalez, V
    Univ Valencia, Dept Ingn Elect, Valencia, Spain..
    Harkness-Brennan, L. J.
    Univ Liverpool, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England..
    Hess, H.
    Univ Cologne, Inst Kernphys, Zulpicher Str 77, D-50937 Cologne, Germany..
    Jungclaus, A.
    CSIC, Inst Estruct Mat, E-28006 Madrid, Spain..
    Korten, W.
    CEA, DRF, IRFU, Ctr CEA Saclay, F-91191 Gif Sur Yvette, France..
    Labiche, M.
    STFC Daresbury Lab, Warrington WA4 4AD, Cheshire, England..
    Lefevre, A.
    CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France..
    Menegazzo, R.
    Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy..
    Mengoni, D.
    Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy.;Univ Padua, Dipartimento Fis & Astron, I-35131 Padua, Italy..
    Million, B.
    Ist Nazl Fis Nucl, Sez Milano, Milan, Italy..
    Napoli, D. R.
    Ist Nazl Fis Nucl, Lab Nazl Legnaro, Via Romea 4, I-35020 Legnaro, Italy..
    Pullia, A.
    Ist Nazl Fis Nucl, Sez Milano, Milan, Italy.;Univ Milan, Dipartimento Fis, I-20133 Milan, Italy..
    Quintana, B.
    Univ Salamanca, Lab Radiac Ionizantes, E-37008 Salamanca, Spain..
    Ralet, D.
    Univ Paris Saclay, Univ Paris Sud, CSNSM, CNRS,IN2P3, F-91405 Orsay, France.;Tech Univ Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany.;Helmholtzzentrum Schwerionenforsch GmbH, GSI, D-64291 Darmstadt, Germany..
    Recchia, F.
    Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy.;Univ Padua, Dipartimento Fis & Astron, I-35131 Padua, Italy..
    Reiter, P.
    Univ Cologne, Inst Kernphys, Zulpicher Str 77, D-50937 Cologne, Germany..
    Saillant, F.
    CNRS, GANIL, CEA, IN2P3,DRF, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France..
    Salsac, M. D.
    CEA, DRF, IRFU, Ctr CEA Saclay, F-91191 Gif Sur Yvette, France..
    Sanchis, E.
    Univ Valencia, Dept Ingn Elect, Valencia, Spain..
    Stezowski, O.
    Univ Lyon 1, Univ Lyon, CNRS, IN2P3,UMR5822,IPNL, 4 Rue Enrico Fermi, F-69622 Villeurbanne, France..
    Theisen, Ch
    CEA, DRF, IRFU, Ctr CEA Saclay, F-91191 Gif Sur Yvette, France..
    Valiente-Dobon, J. J.
    Ist Nazl Fis Nucl, Lab Nazl Legnaro, Via Romea 4, I-35020 Legnaro, Italy..
    Zielinska, M.
    CEA, DRF, IRFU, Ctr CEA Saclay, F-91191 Gif Sur Yvette, France..
    Effects of one valence proton on seniority and angular momentum of neutrons in neutron-rich(51)( 122-)(131)Sb isotopes2019In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 99, no 6, article id 064302Article in journal (Refereed)
    Abstract [en]

    Background: Levels fulfilling the seniority scheme and relevant isomers are commonly observed features in semimagic nuclei; for example, in Sn isotopes (Z = 50). Seniority isomers in Sn, with dominantly pure neutron configurations, directly probe the underlying neutron-neutron (vv) interaction. Furthermore, an addition of a valence proton particle or hole, through neutron-proton (v pi) interaction, affects the neutron seniority as well as the angular momentum. Purpose: Benchmark the reproducibility of the experimental observables, like the excitation energies (E-x) and the reduced electric-quadrupole transition probabilities [B(E2)], with the results obtained from shell-model interactions for neutron-rich Sn and Sb isotopes with N < 82. Study the sensitivity of the aforementioned experimental observables to the model interaction components. Furthermore, explore from a microscopic point of view the structural similarity between the isomers in Sn and Sb, and thus the importance of the valence proton. Methods: The neutron-rich Sb122-131 isotopes were produced as fission fragments in the reaction Be-9(U-238, f) with 6.2 MeV/u beam energy. A unique setup, consisting of AGATA, VAMOS++, and EXOGAM detectors, was used which enabled the prompt-delayed gamma-ray spectroscopy of fission fragments in the time range of 100 ns to 200 mu s. Results: New isomers and prompt and delayed transitions were established in the even-A Sb122-131 isotopes. In the odd-A Sb122-131 isotopes, new prompt and delayed gamma-ray transitions were identified, in addition to the confirmation of the previously known isomers. The half-lives of the isomeric states and the B(E2) transition probabilities of the observed transitions depopulating these isomers were extracted. Conclusions: The experimental data was compared with the theoretical results obtained in the framework of large-scale shell-model (LSSM) calculations in a restricted model space. Modifications of several components of the shell-model interaction were introduced to obtain a consistent agreement with the excitation energies and the B(E2) transition probabilities in neutron-rich Sn and Sb isotopes. The isomeric configurations in Sn and Sb were found to be relatively pure. Furthermore, the calculations revealed that the presence of a single valence proton, mainly in the g(7/2) orbital in Sb isotopes, leads to significant mixing (due to the v pi interaction) of (i) the neutron seniorities (upsilon(v)) and (ii) the neutron angular momentum (I-v). The above features have a weak impact on the excitation energies, but have an important impact on the B(E2) transition probabilities. In addition, a constancy of the relative excitation energies irrespective of neutron seniority and neutron number in Sn and Sb was observed.

  • 21.
    Cai, Boshuai
    et al.
    Sun Yat Sen Univ, Sino French Inst Nucl Engn & Technol, Zhuhai 519082, Guangdong, Peoples R China..
    Chen, Guangshang
    Sun Yat Sen Univ, Sino French Inst Nucl Engn & Technol, Zhuhai 519082, Guangdong, Peoples R China..
    Xu, Jiongyu
    Sun Yat Sen Univ, Sino French Inst Nucl Engn & Technol, Zhuhai 519082, Guangdong, Peoples R China..
    Yuan, Cenxi
    Sun Yat Sen Univ, Sino French Inst Nucl Engn & Technol, Zhuhai 519082, Guangdong, Peoples R China..
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Yao, Yuan
    Beijing Normal Univ, Coll Nucl Sci & Technol, Beijing 100875, Peoples R China..
    alpha decay half-life estimation and uncertainty analysis2020In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 101, no 5, article id 054304Article in journal (Refereed)
    Abstract [en]

    Background: alpha decay is one of the most important decay modes of atomic nuclei. The half-life of alpha decay provides valuable information for nuclear structure study. Many theoretical models and empirical formulas have been suggested to describe the half-life of alpha decay as a function of decay energy (Q(alpha)), atomic number (Z), nucleon number (A), and other related variables. However, the analysis of theoretical uncertainty is rarely done for those alpha decay models. Purpose: We aim to perform a systematic and detailed study on the theoretical uncertainty of existing alpha decay formulas based on statistical methods. Methods: The nonparametric bootstrap method is used to evaluate the uncertainties of two alpha decay formulas, the universal decay law (UDL) and the new Geiger-Nuttall law (NGNL). Such a method can simultaneously obtain the uncertainty of each parameter, the correlation between each pair of parameters, and the total, statistical, and systematic uncertainties of each formula. Both even-even (ee) nuclei and odd-A (oA) nuclei are used in the analysis. The collected data are separated into three parts: ee nuclei, oA nuclei without spin or parity change (oA_nc), and oA nuclei with spin and/or parity change (oA_c). Based on the residues between observed data and corresponding calculations, the statistical and systematic uncertainties are decomposed from the total uncertainty, from which one can clarify the effects from the shell structure, pairing, and angular momentum change on describing alpha decay half-life. Results: If N > 126 and N <= 126 nuclei are considered together, the systematic uncertainty of residues between observed and predicted half-lives are larger than if those groups are considered separately. Without a shell correction term, a much larger systematic uncertainty is found if parameters obtained for N <= 126 nuclei are used to describe the half-lives of N > 126 nuclei. Based on the Bohr-Sommerfeld quantization condition and simple assumptions, a detailed shell correction term is obtained for N > 126 nuclei, for which the value is similar to that in NGNL. A global hindrance on the alpha decay process is found in oA_nc (oA_c) nuclei compared with ee (oA_nc) nuclei. If parameters obtained from ee (oA_nc) nuclei are used, the half-lives of oA_nc (oA_c) nuclei are generally underestimated with large systematic uncertainties, which can be related to the contribution of pairing effect and angular momentum. The parameter of angular momentum term in NGNL is obtained with large uncertainty and very sensitive to the selections of the dataset. The recently observed superallowed decay from Te-104 to Sn-100 is also discussed based on uncertainty analysis. Conclusions: The theoretical uncertainty of existing alpha decay formulas is successfully evaluated by the nonparametric bootstrap method, which simultaneously indicates the important effect in alpha decay, such as the shell effect and the pairing effect. In addition, statistical results show strong correlations between the parameters of the second and third terms in both UDL and NGNL, which demands further investigations.

  • 22.
    Ciemala, M.
    et al.
    Inst Nucl Phys, PAN, PL-31342 Krakow, Poland..
    Atac Nyberg, Ayse
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Simonis, J.
    Johannes Gutenberg Univ Mainz, Inst Kernphys & PRISMA Cluster Excellence, D-55128 Mainz, Germany..
    Testing ab initio nuclear structure in neutron-rich nuclei: Lifetime measurements of second 2(+) state in C-16 and O-202020In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 101, no 2, article id 021303Article in journal (Refereed)
    Abstract [en]

    To test the predictive power of ab initio nuclear structure theory, the lifetime of the second 2(+) state in neutron-rich O-20, tau(2(2)(+)) = 150(-30)(+80) fs, and an estimate for the lifetime of the second 2(+) state in C-16 have been obtained for the first time. The results were achieved via a novel Monte Carlo technique that allowed us to measure nuclear state lifetimes in the tens-to-hundreds of femtoseconds range by analyzing the Doppler-shifted gamma-transition line shapes of products of low-energy transfer and deep-inelastic processes in the reaction O-18 (7.0 MeV/u) + Ta-181. The requested sensitivity could only be reached owing to the excellent performances of the Advanced gamma-Tracking Array AGATA, coupled to the PARIS scintillator array and to the VAMOS++ magnetic spectrometer. The experimental lifetimes agree with predictions of ab initio calculations using two- and three-nucleon interactions, obtained with the valence-space in-medium similarity renormalization group for O-20 and with the no-core shell model for C-16. The present measurement shows the power of electromagnetic observables, determined with high-precision gamma spectroscopy, to assess the quality of first-principles nuclear structure calculations, complementing common benchmarks based on nuclear energies. The proposed experimental approach will be essential for short lifetime measurements in unexplored regions of the nuclear chart, including r-process nuclei, when intense beams, produced by Isotope Separation On-Line (ISOL) techniques, become available.

  • 23.
    Clement, E.
    et al.
    CEA DRF CNRS IN2P3, GANIL, Bd Henri Becquerel,BP 55027, F-14076 Caen, France..
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Dobon, J. J. Valiente
    INFN, Lab Nazl Legnaro, I-35020 Padua, Italy..
    et al.,
    Spectroscopic quadrupole moments in 124Xe2023In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 107, no 1, article id 014324Article in journal (Refereed)
    Abstract [en]

    Background: The Xe isotopic chain with four valence protons above the Z = 50 shell closure is an ideal laboratory for the study of the evolution of nuclear deformation. At the N = 82 shell closure, 136Xe presents all characteristics of a doubly closed shell nucleus with a spherical shape. In the very neutron-deficient isotopes close to N = 50, the alpha-decay chain of Xe was investigated to probe the radioactive decay properties near the drip-line and the magicity of 100Sn. Additionally, the Xe isotopes present higher order symmetries in the nuclear deformation such as the octupole degree of freedom near N = 60 and N = 90 or O(6) symmetry in stable isotopes.Purpose: The relevance of the O(6) symmetry has been investigated by measuring the spectroscopic quadrupole moment of the first excited states in 124Xe. In the O(6) symmetry limit, the spectroscopic quadrupole moment of collective states is expected to be null.Method: A stable 124Xe beam with energies of 4.03A MeV and 4.11A MeV was used to bombard a natW target at the GANIL facility. Excited states were populated via the safe Coulomb excitation reaction. The collision of the heavy ions with a large Z at low energy make this reaction sensitive to the diagonal E2 matrix element of the excited states. The recoils were detected in the VAMOS++ magnetic spectrometer and the gamma rays in the AGATA tracking array. The least squares fitting code GOSIA was used for the analysis to extract both E2 and M1 transitional and E2 diagonal matrix elements.Results: The rotational ground state band was populated up to the 8+1 state as well as the 2+2 and 4+2 states. Using high precision spectroscopic data to constrain the GOSIA fit, the spectroscopic quadrupole moments of the 2+1 , 4+1 , and 6+1 states were determined for the first time. Conclusions: The spectroscopic quadrupole moments were found to be negative, large, and constant in the ground state band underlining the prolate axially deformed ground state band of 124Xe. The present experimental data confirm that the is broken in 124Xe.

  • 24.
    Cortes, M. L.
    et al.
    RIKEN, Nishina Ctr, 2-1 Hirosawa, Wako, Saitama 3510198, Japan.;Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy..
    Liu, H. N.
    KTH, School of Engineering Sciences (SCI), Physics. Univ Paris Saclay, IRFU, CEA, F-91191 Gif Sur Yvette, France.;Tech Univ Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany..
    Aktas, Özge
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Zanetti, L.
    Tech Univ Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany..
    N=32 shell closure below calcium: Low-lying structure of Ar-502020In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 102, no 6, article id 064320Article in journal (Refereed)
    Abstract [en]

    Low-lying excited states in the N = 32 isotope Ar-50 were investigated by in-beam gamma-ray spectroscopy following proton- and neutron-knockout, multinucleon removal, and proton inelastic scattering at the RIKEN Radioactive Isotope Beam Factory. The energies of the two previously reported transitions have been confirmed, and five additional states are presented for the first time, including a candidate for a 3(-) state. The level scheme built using gamma gamma coincidences was compared to shell-model calculations in the sd-pf model space and to ab initio predictions based on chiral two- and three-nucleon interactions. Theoretical proton- and neutron-knockout cross sections suggest that two of the new transitions correspond to 2(+) states, while the previously proposed 4(1)(+) state could also correspond to a 2(+) state.

  • 25. Cui, J. P.
    et al.
    Zhang, Y. L.
    Zhang, S.
    Wang, Yanzhao
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    alpha-decay half-lives of superheavy nuclei2018In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 97, no 1, article id 014316Article in journal (Refereed)
    Abstract [en]

    The alpha-decay half-lives of superheavy nuclei (SHN) with Z >= 104 are investigated by employing the effective liquid drop model (ELDM). By comparison between the calculated half-lives and the experimental ones, it is shown that the ELDM is a successful model to reproduce the experimental half-lives of SHN. Within the ELDM the alpha-decay half-lives of Z = 118-120 isotopes are predicted by inputting the alpha-decay energy (Q(alpha)) values extracted from the newest Weizsacker-Skyrme-4 (WS4) model, the finite-range droplet model (FRDM), the Kourra-Tachibaba-Uno-Yamada (KTUY) formula, and the Hartree-Fock-Bogoliubovmean field with the D1S Gogny force (GHFB). It is found that the shell effects at N = 178 and 184 are evident by analyzing the Q(alpha) values and half-lives versus the neutron number N. Because the WS4 Q(alpha) values have the smallest rms deviation, the predicted alpha-decay half-lives could be more accurate than the ones of other models, which will be helpful for future experiments.

  • 26. Das, B.
    et al.
    Cederwall, B.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Aktas, Özge
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Petrovic, Jana
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Zimba, G.
    Univ Jyvaskyla, Seminaarinkatu 15, Jyvaskyla 40014, Finland..
    Nature of seniority symmetry breaking in the semimagic nucleus Ru-942022In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 105, no 3, article id L031304Article in journal (Refereed)
    Abstract [en]

    Direct lifetime measurements via gamma -gamma coincidences using a fast timing detector array consisting of LaBr3(Ce) scintillators has been applied to determine the lifetime of low-lying states in the semimagic (N = 50) nucleus Ru-94. The experiment was carried out as the first in a series of "FAIR-0" experiments with the DESPEC experimental setup at the Facility for Antiproton and Ion Research (FAIR). Excited states in Ru-94 were populated primarily via the beta-delayed proton emission of Pd-95 nuclei, produced in the projectile fragmentation of an 850 MeV/nucleon Xe-124 beam impinging on a 4 g/cm(2) Be-9 target. While the deduced E2 strength for the 2(+) -> 0(+) transition in the yrast cascade follows the expected behavior for conserved seniority symmetry, the intermediate 4(+) -> 2(+) transition exhibits a drastic enhancement of transition strength in comparison with pure-seniority model predictions as well as standard shell model predictions in the f pg proton hole space with respect to doubly magic Sn-100. The anomalous behavior is ascribed to a subtle interference between the wave function of the lowest seniority v = 2, I-pi = 4(+) state and that of a close-lying v = 4 state that exhibits partial dynamic symmetry. In addition, the observed strongly prohibitive 6(+) -> 4(+) transition can be attributed to the same mechanism but with a destructive interference. It is noted that such effects may provide stringent tests of the nucleon-nucleon interactions employed in state-of-the-art theoretical model calculations.

  • 27.
    Davies, P. J.
    et al.
    Univ York, York YO10 5DD, N Yorkshire, England..
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Zhu, Y.
    Tokyo Univ Sci, Noda, Chiba 2788510, Japan..
    Toward the limit of nuclear binding on the N = Z line: Spectroscopy of Cd-962019In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 99, no 2, article id 021302Article in journal (Refereed)
    Abstract [en]

    A gamma -decaying isomeric state (tau(1/2) = 197(-17)(+19) ns) has been identified in Cd-96, which is one alpha particle away from the last known bound N = Z nucleus, Sn-100. Comparison of the results with shell-model calculations has allowed a tentative experimental level scheme to be deduced and the isomer to be interpreted as a medium-spin negative-parity spin trap based on the coupling of isoscalar (T = 0) and isovector (T = 1) neutron-proton pairs. The data also suggest evidence for the population of a 9(+) T = 1 state, which is predicted by shell-model calculations to be yrast. Such a low-lying T = 1 state, which is unknown in lighter mass even-even self-conjugate nuclei, can also be interpreted in terms of the coupling of T = 0 and T = 1 neutron-proton pairs.

  • 28.
    Ding, B.
    et al.
    Chinese Acad Sci, Inst Modern Phys, Key Lab High Precis Nucl Spect, Lanzhou 730000, Peoples R China.;Univ Chinese Acad Sci, Sch Nucl Sci & Technol, Beijing 100049, Peoples R China..
    Petrache, C. M.
    Univ Paris Saclay, CNRS IN2P3, IJCLab, F-91405 Orsay, France..
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Zikhali, B. R.
    Natl Res Fdn, iThemba LABS, POB 722, ZA-7129 Somerset West, South Africa.;Univ Western Cape, Dept Phys, Private Bag X17, ZA-7535 Bellville, South Africa..
    Signature splitting of the g(7/2)[404]7/2(+) bands in Ba-131 and Ce-1332021In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 104, no 6, article id 064304Article in journal (Refereed)
    Abstract [en]

    Excited states in Ba-131 and Ce-133 were studied using in-beam gamma-ray spectroscopy through the Sn-122(C-13, 4n) Ba-133 and Te-125(C-12, 4n) Ce-133 reactions, respectively. A strongly coupled band, associated with the nu g(7/2) [404]7/2(+) configuration, was identified in Ba-131 and Ce-133. It is the first time to observe the nu g(7/2) [404]7/2(+) bands in the N = 75 isotones. The signature partners exhibit considerable energy splitting in comparison with those in the pi g(7/2) [404]7/2(+) bands in the odd-A Ta and Re isotopes. Extensive cranked shell model and quasiparticle-plus-triaxial-rotor model calculations reveal the origin of the signature splitting, which depends not only on the triaxiality, but also on the configuration mixing with nearby low- j orbitals.

  • 29.
    Doncel, Maria
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Qi, C.
    Cullen, D. M.
    Hodge, D.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Taylor, M. J.
    Procter, M.
    Giles, M.
    Auranen, K.
    Grahn, T.
    Greenlees, P. T.
    Jakobsson, U.
    Julin, R.
    Juutinen, S.
    Herzáň, A.
    Konki, J.
    Pakarinen, J.
    Partanen, J.
    Peura, P.
    Rahkila, P.
    Ruotsalainen, P.
    Sandzelius, M.
    Sarén, J.
    Scholey, C.
    Sorri, J.
    Stolze, S.
    Uusitalo, J.
    Spin-dependent evolution of collectivity in Te 1122017In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 96, no 5, article id 051304Article in journal (Refereed)
    Abstract [en]

    The evolution of collectivity with spin along the yrast line in the neutron-deficient nucleus Te112 has been studied by measuring the reduced transition probability of excited states in the yrast band. In particular, the lifetimes of the 4+ and 6+ excited states have been determined by using the recoil distance Doppler-shift method. The results are discussed using both large-scale shell-model and total Routhian surface calculations.

  • 30.
    Doncel, Maria
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics.
    Li, Hongjie J.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Jakobsson, Ulrika
    KTH, School of Engineering Sciences (SCI), Physics.
    Auranen, K.
    Boenig, S.
    Drummond, M. C.
    Grahn, T.
    Greenlees, P. T.
    Herzan, A.
    Joss, D. T.
    Julin, R.
    Juutinen, S.
    Konki, J.
    Kroell, T.
    Leino, M.
    McPeake, C.
    O'Donnell, D.
    Page, R. D.
    Pakarinen, J.
    Partanen, J.
    Peura, P.
    Rahkila, P.
    Ruotsalainen, P.
    Sandzelius, M.
    Saren, J.
    Saygi, B.
    Scholey, C.
    Sorri, J.
    Stolze, S.
    Taylor, M. J.
    Thornthwaite, A.
    Uusitalo, J.
    Lifetime measurements of excited states in W-162 and W-164 and the evolution of collectivity in rare-earth nuclei2017In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 95, no 4, article id 044321Article in journal (Refereed)
    Abstract [en]

    Lifetimes of the first excited 2(+) states in the extremely neutron- deficient W-162 and W-164 nuclei have been measured using the recoil distance Doppler shift technique. Experimental B(E2) data for the isotopic chains of hafnium, tungsten, and osmium, from the midshell region near the beta-stability line towards the N = 82 closed shell and the most neutron-deficient nuclides, are compared with predictions of nuclear deformations and 2(1)(+) -> 0(g.s)(.+) reduced transition strengths from different classes of state-of-the-art theoretical model calculations. The results reveal striking differences and deficiencies in the predictive power of current nuclear structure models.

  • 31.
    Elekes, Z.
    et al.
    Atomki, POB 51, H-4001 Debrecen, Hungary.;Univ Debrecen, Egyet Ter 1, H-4032 Debrecen, Hungary..
    Liu, Haichun
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum and Biophotonics. Tech Univ Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany.;Univ Paris Saclay, CEA, IRFU, F-91191 Gif Sur Yvette, France..
    Aktas, Özge
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Zanetti, L.
    Tech Univ Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany..
    "Southwestern" boundary of the N=40 island of inversion: First study of low-lying bound excited states in 59V and 61V2022In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 106, no 6, article id 064321Article in journal (Refereed)
    Abstract [en]

    The low-lying level structure of 59V and 61V was investigated for the first time. The neutron knockout reaction and inelastic proton scattering were applied for 61V while the neutron knock-out reaction provided the data for 59V. Four and five new transitions were determined for 59V and 61V, respectively. Based on the comparison to our shell-model calculations using the Lenzi-Nowacki-Poves-Sieja (LNPS) interaction, three of the observed ?? rays for each isotope could be placed in the level scheme and assigned to the decay of the first 11/2??? and 9/2??? levels. The (p, p') excitation cross sections for 61V were analyzed by the coupled-channels formalism assuming quadrupole plus hexadecapole deformations. Due to the role of the hexadecapole deformation, 61V could not be unambiguously placed on the island of inversion.

  • 32.
    Filmer, E. K.
    et al.
    Department of Physics, University of Adelaide, Adelaide, Australia.
    Leopold, Alexander
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Lundberg, Olof
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Lund-Jensen, Bengt
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ohm, Christian
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ripellino, Giulia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics. Department of Physics, Royal Institute of Technology, Stockholm, Sweden.
    Shaheen, Rabia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Shope, David R.
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Tackmann, K.
    Institut für Experimentalphysik, Universität Hamburg, Hamburg, Germany.
    et al.,
    Measurement of substructure-dependent jet suppression in Pb+Pb collisions at 5.02 TeV with the ATLAS detector2023In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 107, no 5, article id e054909Article in journal (Refereed)
    Abstract [en]

    The ATLAS detector at the Large Hadron Collider has been used to measure jet substructure modification and suppression in Pb+Pb collisions at a nucleon–nucleon center-of-mass energy √sNN = 5.02 TeV in comparison with proton–proton (pp) collisions at √s = 5.02 TeV. The Pb+Pb data, collected in 2018, have an integrated luminosity of 1.72 nb−1, while the ppdata, collected in 2017, have an integrated luminosity of 260 pb−1. Jets used in this analysis are clustered using the anti-kt algorithm with a radius parameter R = 0.4. The jet constituents, defined by both tracking and calorimeter information, are used to determine the angular scale rg of the first hard splitting inside the jet by reclustering them using the Cambridge–Aachen algorithm and employing the soft-drop grooming technique. The nuclear modification factor, RAA, used to characterize jet suppression in Pb+Pb collisions, is presented differentially in rg, jet transverse momentum, and in intervals of collision centrality. The RAA value is observed to depend significantly on jet rg. Jets produced with the largest measured rg are found to be twice as suppressed as those with the smallest rg in central Pb+Pb collisions. The RAA values do not exhibit a strong variation with jet pT in any of the rg intervals. The rg and pT dependence of jet RAA is qualitatively consistent with a picture of jet quenching arising from coherence and provides the most direct evidence in support of this approach.

  • 33. Filmer, E. K.
    et al.
    Leopold, Alexander
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Lundberg, Olof
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Lund-Jensen, Bengt
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Ohm, Christian
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Shaheen, Rabia
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Tipton, P.
    Department of Physics, Yale University, New Haven, Connecticut, USA.
    et al.,
    Measurements of the suppression and correlations of dijets in Xe+Xe collisions at Formula Presented TeV2023In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 108, no 2, article id 024906Article in journal (Refereed)
    Abstract [en]

    Measurements of the suppression and correlations of dijets is performed using 3 µ b − 1 of Xe+Xe data at s N N = 5.44 TeV collected with the ATLAS detector at the CERN Large Hadron Collider. Dijets with jets reconstructed using the R = 0.4 anti- k t algorithm are measured differentially in jet p T over the range of 32 to 398 GeV and the centrality of the collisions. Significant dijet momentum imbalance is found in the most central Xe+Xe collisions, which decreases in more peripheral collisions. Results from the measurement of per-pair normalized and absolutely normalized dijet p T balance are compared with previous Pb + Pb measurements at s N N = 5.02 TeV. The differences between the dijet suppression in Xe+Xe and Pb + Pb are further quantified by the ratio of pair nuclear-modification factors. The results are found to be consistent with those measured in Pb + Pb data when compared in classes of the same event activity and when taking into account the difference between the center-of-mass energies of the initial parton scattering process in Xe+Xe and Pb + Pb collisions. These results should provide input for a better understanding of the role of energy density, system size, path length, and fluctuations in the parton energy loss.

  • 34. Gatera, A.
    et al.
    Belgya, T.
    Geerts, W.
    Göök, A.
    Hambsch, F. -J
    Lebois, M.
    Maróti, B.
    Moens, A.
    Oberstedt, A.
    Oberstedt, S.
    Postelt, F.
    Qi, L.
    Szentmiklósi, L.
    Sibbens, G.
    Vanleeuw, D.
    Vidali, M.
    Zeiser, F.
    Prompt-fission γ -ray spectral characteristics from Pu 239 (nth,f)2017In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 95, no 6, article id 064609Article in journal (Refereed)
    Abstract [en]

    In this paper we present new results for prompt fission γ-ray spectral characteristics from the thermal neutron induced fission of Pu∗240. The measured spectra were unfolded by using the detectors' response functions, simulated with geant4. We obtained in average per fission a γ-ray multiplicity Mγ=(7.35±0.12), a mean photon energy ϵγ=(0.85±0.02) MeV, and an average total energy released in fission Ēγ,tot=(6.27±0.11) MeV. Our results are in good agreement with historical data measured in the 1970s by Verbinski et al. and results from recent calculations in the framework of Monte Carlo Hauser-Feshbach models. Our measured average total energy is slightly smaller than the one deduced previously and present in evaluated data. From this we conclude that the Pu239(nth,f) reaction may be ruled out as possible source of γ heating underestimation, when compared with benchmark calculations based on existing nuclear data.

  • 35. Girard-Alcindor, V.
    et al.
    Mercenne, A.
    Stefan, I.
    De Oliveira Santos, F.
    Michel, N.
    Płoszajczak, M.
    Assié, M.
    Lemasson, A.
    Clément, E.
    Flavigny, F.
    Matta, A.
    Ramos, D.
    Rejmund, M.
    Dudouet, J.
    Ackermann, D.
    Adsley, P.
    Assunção, M.
    Bastin, B.
    Beaumel, D.
    Benzoni, G.
    Borcea, R.
    Boston, A. J.
    Brugnara, D.
    Cáceres, L.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Celikovic, I.
    Chudoba, V.
    Ciemala, M.
    Collado, J.
    Crespi, F. C. L.
    D'Agata, G.
    De France, G.
    Delaunay, F.
    Diget, C.
    Domingo-Pardo, C.
    Eberth, J.
    Fougères, C.
    Franchoo, S.
    Galtarossa, F.
    Georgiadou, A.
    Gibelin, J.
    Giraud, S.
    González, V.
    Goyal, N.
    Gottardo, A.
    Goupil, J.
    Grévy, S.
    Guimaraes, V.
    Hammache, F.
    Harkness-Brennan, L. J.
    Hess, H.
    Jovančević, N.
    Judson Oliver, D. S.
    Kamalou, O.
    Kamenyero, A.
    Kiener, J.
    Korten, W.
    Koyama, S.
    Labiche, M.
    Lalanne, L.
    Lapoux, V.
    Leblond, S.
    Lefevre, A.
    Lenain, C.
    Leoni, S.
    Li, H.
    Lopez-Martens, A.
    Maj, A.
    Matea, I.
    Menegazzo, R.
    Mengoni, D.
    Meyer, A.
    Million, B.
    Monteagudo, B.
    Morfouace, P.
    Mrazek, J.
    Niikura, M.
    Piot, J.
    Podolyak, Z.
    Portail, C.
    Pullia, A.
    Quintana, B.
    Recchia, F.
    Reiter, P.
    Rezynkina, K.
    Roger, T.
    Rojo, J. S.
    Rotaru, F.
    Salsac, M. D.
    Sánchez Benítez, A. M.
    Sanchis, E.
    Şenyigit, M.
    De Séréville, N.
    Siciliano, M.
    Simpson, J.
    Sohler, D.
    Sorlin, O.
    Stanoiu, M.
    Stodel, C.
    Suzuki, D.
    Theisen, C.
    Thisse, D.
    C.thomas, J.
    Ujic, P.
    Valiente-Dobón, J. J.
    Zielińska, M.
    New narrow resonances observed in the unbound nucleus F 152022In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 105, no 5, article id L051301Article in journal (Refereed)
    Abstract [en]

    The structure of the unbound F15 nucleus is investigated using the inverse kinematics resonant scattering of a radioactive O14 beam impinging on a CH2 target. The analysis of H1(O14,p)O14 and H1(O14,2p)N13 reactions allowed the confirmation of the previously observed narrow 1/2- resonance, near the two-proton decay threshold, and the identification of two new narrow 5/2- and 3/2- resonances. The newly observed levels decay by 1p emission to the ground of O14, and by sequential 2p emission to the ground state of N13 via the 1- resonance of O14. Gamow shell model (GSM) analysis of the experimental data suggests that the wave functions of the 5/2- and 3/2- resonances may be collectivized by the continuum coupling to nearby 2p- and 1p-decay channels. The observed excitation function H1(O14,p)O14 and resonance spectrum in F15 are well reproduced in the unified framework of the GSM.

  • 36.
    Goldkuhle, A.
    et al.
    Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany..
    Atac Nyberg, Ayse
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Zielinska, M.
    Univ Paris Saclay, CEA, Irfu, F-91191 Gif Sur Yvette, France..
    et al.,
    Lifetime measurements in Ti-52,Ti-54 to study shell evolution toward N=322019In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 100, no 5, article id 054317Article in journal (Refereed)
    Abstract [en]

    Lifetimes of the excited states in the neutron-rich Ti-52,Ti-54 nuclei, produced in a multinucleon-transfer reaction, were measured by employing the Cologne plunger device and the recoil-distance Doppler-shift method. The experiment was performed at the Grand Accelerateur National d'Ions Lourds facility by using the Advanced Gamma Tracking Array for the gamma-ray detection, coupled to the large-acceptance variable mode spectrometer for an event-by-event particle identification. A comparison between the transition probabilities obtained from the measured lifetimes of the 2(1)(+) to 8(1)(+) yrast states in Ti-52,Ti-54 and that from the shell-model calculations based on the well-established GXPF1A, GXPF1B, and KB3G fp shell interactions support the N = 32 subshell closure. The B(E2) values for Ti-52 determined in this work are in disagreement with the known data, but are consistent with the predictions of the shell-model calculations and reduce the previously observed pronounced staggering across the even-even titanium isotopes.

  • 37. Göök, A.
    et al.
    Eckardt, C.
    Enders, J.
    Freudenberger, M.
    Oberstedt, A.
    Oberstedt, S.
    Correlated mass, energy, and angular distributions from bremsstrahlung-induced fission of U 234 and Th 232 in the energy region of the fission barrier2017In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 96, no 4, article id 044301Article in journal (Refereed)
    Abstract [en]

    The bremstrahlung-induced fission of U234 and Th232 has been studied at the superconducting Darmstadt linear accelerator (S-DALINAC) in the excitation energy region close to the fission barrier. Fission-fragment mass and total kinetic energy (TKE) distributions from U234 were studied for the first time in this energy region. The results have been analysed in terms of fission modes, and a dominant yield of the mass-asymmetric standard-2 mode was found in both nuclei. No strong dependence of the fission-mode weights on the excitation energy of the compound nucleus was found. Correlations among mass, TKE, and angular distributions have also been investigated. A correlation in the form of an increased anisotropy for far-asymmetric masses and low TKE were found in both fissioning systems. A possible interpretation of this correlation in terms of fission modes is discussed. 

  • 38. Göök, A.
    et al.
    Hambsch, F. -J
    Oberstedt, S.
    Vidali, M.
    Prompt neutrons in correlation with fission fragments from U 235 (n,f)2018In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 98, no 4, article id 044615Article in journal (Refereed)
    Abstract [en]

    Improved knowledge of prompt emission in fission has significant implications for our understanding of the fission process. It is also important for improving nuclear data evaluation, with impact on applications. The correlation between prompt neutrons and fragments emitted in binary neutron induced fission of U235 has been studied at the GELINA facility. The experiment employs an array of proton recoil scintillators and a position-sensitive twin ionization chamber. This experimental arrangement permits measurement of the correlations between neutron emission, fragment angle, and mass and energy of the fission fragments. In this article, we present results on prompt fission neutron energy and multiplicity correlations with mass and total kinetic energy of the fission fragments. Results from the present measurement shows distinct differences compared to earlier studies of the correlated fission fragment and prompt neutron emission quantities. The differences with respect to earlier investigations are interpreted as improved fission fragment energy resolution in the present measurement. The present result supports several recent model calculations of prompt neutron and fission fragment correlations. 

  • 39.
    Hadynska-Klek, K.
    et al.
    Univ Warsaw, Heavy Ion Lab, Pasteura 5A, PL-02093 Warsaw, Poland.;Univ Warsaw, Fac Phys, PL-00681 Warsaw, Poland.;Univ Oslo, Dept Phys, N-0316 Oslo, Norway.;INFN Lab Nazl Legnaro, Viale Univ 2, I-35020 Legnaro, Italy.;Univ Surrey, Dept Phys, Guildford GU2 7XH, Surrey, England..
    Napiorkowski, P. J.
    Univ Warsaw, Heavy Ion Lab, Pasteura 5A, PL-02093 Warsaw, Poland..
    Zielinska, M.
    Univ Warsaw, Heavy Ion Lab, Pasteura 5A, PL-02093 Warsaw, Poland.;Univ Paris Saclay, CEA, Irfu, F-91191 Gif Sur Yvette, France..
    Srebrny, J.
    Univ Warsaw, Heavy Ion Lab, Pasteura 5A, PL-02093 Warsaw, Poland..
    Maj, A.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland..
    Azaiez, F.
    Inst Phys Nucl Orsay, F-91400 Orsay, France..
    Dobon, J. J. Valiente
    INFN Lab Nazl Legnaro, Viale Univ 2, I-35020 Legnaro, Italy..
    Kicinska-Habior, M.
    Univ Warsaw, Fac Phys, PL-00681 Warsaw, Poland..
    Nowacki, F.
    Univ Strasbourg, IPHC, CNRS, UMR7178, 23 Rue Loess, F-67037 Strasbourg, France..
    Naidja, H.
    Univ Strasbourg, IPHC, CNRS, UMR7178, 23 Rue Loess, F-67037 Strasbourg, France.;GSI Helmholtzzentrum Schwerionenforsch GmbH, D-64291 Darmstadt, Germany.;Univ Constantine 1, LPMS, Route Ain El Bey, Constantine 25000, Algeria..
    Bounthong, B.
    Univ Strasbourg, IPHC, CNRS, UMR7178, 23 Rue Loess, F-67037 Strasbourg, France..
    Rodriguez, T. R.
    Univ Autonoma Madrid, Dept Fis Teor, Madrid, Spain..
    de Angelis, G.
    INFN Lab Nazl Legnaro, Viale Univ 2, I-35020 Legnaro, Italy..
    Abraham, T.
    Univ Warsaw, Heavy Ion Lab, Pasteura 5A, PL-02093 Warsaw, Poland..
    Kumar, G. Anil
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland..
    Bazzacco, D.
    INFN Sez Padova, I-35131 Padua, Italy.;Univ Padua, Dipartimento Fis & Astron, I-35131 Padua, Italy..
    Bellato, M.
    INFN Sez Padova, I-35131 Padua, Italy..
    Bortolato, D.
    INFN Sez Padova, I-35131 Padua, Italy..
    Bednarczyk, P.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland..
    Benzoni, G.
    INFN Sez Milano, I-20133 Milan, Italy..
    Berti, L.
    INFN Lab Nazl Legnaro, Viale Univ 2, I-35020 Legnaro, Italy..
    Birkenbach, B.
    Univ Cologne, Inst Kernphys, Zulpicher Str 77, D-50937 Cologne, Germany..
    Bruyneel, B.
    Univ Cologne, Inst Kernphys, Zulpicher Str 77, D-50937 Cologne, Germany..
    Brambilla, S.
    INFN Sez Milano, I-20133 Milan, Italy..
    Camera, F.
    INFN Sez Milano, I-20133 Milan, Italy.;Univ Milan, Dipartimento Fis, I-20133 Milan, Italy..
    Chavas, J.
    Univ Paris Saclay, CEA, Irfu, F-91191 Gif Sur Yvette, France..
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics. Royal Inst Technol, Dept Phys, SE-10691 Stockholm, Sweden..
    Charles, L.
    Univ Strasbourg, IPHC, CNRS, UMR7178, 23 Rue Loess, F-67037 Strasbourg, France..
    Ciemala, M.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland..
    Cocconi, P.
    INFN Lab Nazl Legnaro, Viale Univ 2, I-35020 Legnaro, Italy..
    Coleman-Smith, P.
    Daresbury Lab, Warrington WA4 4AD, Cheshire, England..
    Colombo, A.
    INFN Sez Padova, I-35131 Padua, Italy..
    Corsi, A.
    INFN Sez Milano, I-20133 Milan, Italy.;Univ Milan, Dipartimento Fis, I-20133 Milan, Italy..
    Crespi, F. C. L.
    INFN Sez Milano, I-20133 Milan, Italy.;Univ Milan, Dipartimento Fis, I-20133 Milan, Italy..
    Cullen, D. M.
    Univ Manchester, Sch Phys & Astron, Schuster Lab, Manchester M13 9PL, Lancs, England..
    Czermak, A.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland..
    Desesquelles, P.
    Univ Paris 11, F-91400 Orsay, France.;CNRS, CSNSM, IN2P3, F-91405 Orsay, France..
    Doherty, D. T.
    Univ Surrey, Dept Phys, Guildford GU2 7XH, Surrey, England.;Univ Paris Saclay, CEA, Irfu, F-91191 Gif Sur Yvette, France.;Univ York, Dept Phys, York YO10 5DD, N Yorkshire, England..
    Dulny, B.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland..
    Eberth, J.
    Univ Cologne, Inst Kernphys, Zulpicher Str 77, D-50937 Cologne, Germany..
    Farnea, E.
    INFN Sez Padova, I-35131 Padua, Italy.;Univ Padua, Dipartimento Fis & Astron, I-35131 Padua, Italy..
    Fornal, B.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland..
    Franchoo, S.
    Inst Phys Nucl Orsay, F-91400 Orsay, France..
    Gadea, A.
    Univ Valencia, CSIC, Inst Fis Corpuscular IFIC, S-46980 Valencia, Spain..
    Giaz, A.
    INFN Sez Milano, I-20133 Milan, Italy.;Univ Milan, Dipartimento Fis, I-20133 Milan, Italy..
    Gottardo, A.
    INFN Lab Nazl Legnaro, Viale Univ 2, I-35020 Legnaro, Italy..
    Grave, X.
    Inst Phys Nucl Orsay, F-91400 Orsay, France..
    Grebosz, J.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland..
    Gorgen, A.
    Univ Oslo, Dept Phys, N-0316 Oslo, Norway..
    Gulmini, M.
    INFN Lab Nazl Legnaro, Viale Univ 2, I-35020 Legnaro, Italy..
    Habermann, T.
    GSI Helmholtzzentrum Schwerionenforsch GmbH, D-64291 Darmstadt, Germany..
    Hess, H.
    Univ Cologne, Inst Kernphys, Zulpicher Str 77, D-50937 Cologne, Germany..
    Isocrate, R.
    INFN Sez Padova, I-35131 Padua, Italy.;Univ Padua, Dipartimento Fis & Astron, I-35131 Padua, Italy..
    Iwanicki, J.
    Univ Warsaw, Heavy Ion Lab, Pasteura 5A, PL-02093 Warsaw, Poland..
    Jaworski, G.
    Univ Warsaw, Heavy Ion Lab, Pasteura 5A, PL-02093 Warsaw, Poland..
    Judson, D. S.
    Univ Liverpool, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England..
    Jungclaus, A.
    CSIC, Inst Estruct Mat, E-28006 Madrid, Spain..
    Karkour, N.
    CNRS, CSNSM, IN2P3, F-91405 Orsay, France..
    Kmiecik, M.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland..
    Karpinski, D.
    Univ Warsaw, Fac Phys, PL-00681 Warsaw, Poland..
    Kisielinski, M.
    Univ Warsaw, Heavy Ion Lab, Pasteura 5A, PL-02093 Warsaw, Poland..
    Kondratyev, N.
    Flerov Lab Nucl React JINR, RU-141980 Dubna, Russia..
    Korichi, A.
    CNRS, CSNSM, IN2P3, F-91405 Orsay, France..
    Komorowska, M.
    Univ Warsaw, Heavy Ion Lab, Pasteura 5A, PL-02093 Warsaw, Poland.;Univ Warsaw, Fac Phys, PL-00681 Warsaw, Poland..
    Kowalczyk, M.
    Univ Warsaw, Heavy Ion Lab, Pasteura 5A, PL-02093 Warsaw, Poland..
    Korten, W.
    Univ Paris Saclay, CEA, Irfu, F-91191 Gif Sur Yvette, France..
    Krzysiek, M.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland.;Horia Hulubei Natl Inst Phys & Nucl Engn, ELI NP, Magurele 077125, Romania..
    Lehaut, G.
    Univ Lyon 1, CNRS, IN2P3, IPN Lyon, F-69622 Villeurbanne, France..
    Leoni, S.
    INFN Sez Milano, I-20133 Milan, Italy.;Univ Milan, Dipartimento Fis, I-20133 Milan, Italy..
    Ljungvall, J.
    CNRS, CSNSM, IN2P3, F-91405 Orsay, France..
    Lopez-Martens, A.
    CNRS, CSNSM, IN2P3, F-91405 Orsay, France..
    Lunardi, S.
    INFN Sez Padova, I-35131 Padua, Italy.;Univ Padua, Dipartimento Fis & Astron, I-35131 Padua, Italy..
    Maron, G.
    INFN Lab Nazl Legnaro, Viale Univ 2, I-35020 Legnaro, Italy..
    Mazurek, K.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland..
    Menegazzo, R.
    INFN Sez Padova, I-35131 Padua, Italy.;Univ Padua, Dipartimento Fis & Astron, I-35131 Padua, Italy..
    Mengoni, D.
    INFN Sez Padova, I-35131 Padua, Italy..
    Merchan, E.
    GSI Helmholtzzentrum Schwerionenforsch GmbH, D-64291 Darmstadt, Germany.;Tech Univ Darmstadt, D-64289 Darmstadt, Germany..
    Meczynski, W.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland..
    Michelagnoli, C.
    INFN Sez Padova, I-35131 Padua, Italy.;Univ Padua, Dipartimento Fis & Astron, I-35131 Padua, Italy..
    Million, B.
    INFN Sez Milano, I-20133 Milan, Italy..
    Myalski, S.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland..
    Napoli, D. R.
    INFN Lab Nazl Legnaro, Viale Univ 2, I-35020 Legnaro, Italy..
    Niikura, M.
    Inst Phys Nucl Orsay, F-91400 Orsay, France..
    Obertelli, A.
    Univ Paris Saclay, CEA, Irfu, F-91191 Gif Sur Yvette, France..
    Ozmen, S. F.
    Univ Warsaw, Heavy Ion Lab, Pasteura 5A, PL-02093 Warsaw, Poland..
    Palacz, M.
    Univ Warsaw, Heavy Ion Lab, Pasteura 5A, PL-02093 Warsaw, Poland..
    Prochniak, L.
    Univ Warsaw, Heavy Ion Lab, Pasteura 5A, PL-02093 Warsaw, Poland..
    Pullia, A.
    INFN Sez Milano, I-20133 Milan, Italy.;Univ Milan, Dipartimento Fis, I-20133 Milan, Italy..
    Quintana, B.
    Univ Salamanca, Dept Fis Fundamental, Lab Radiac Ionizantes, Salamanca, Spain..
    Rampazzo, G.
    INFN Lab Nazl Legnaro, Viale Univ 2, I-35020 Legnaro, Italy..
    Recchia, F.
    INFN Sez Padova, I-35131 Padua, Italy.;Univ Padua, Dipartimento Fis & Astron, I-35131 Padua, Italy..
    Redon, N.
    Univ Lyon 1, CNRS, IN2P3, IPN Lyon, F-69622 Villeurbanne, France..
    Reiter, P.
    Univ Cologne, Inst Kernphys, Zulpicher Str 77, D-50937 Cologne, Germany..
    Rosso, D.
    INFN Lab Nazl Legnaro, Viale Univ 2, I-35020 Legnaro, Italy..
    Rusek, K.
    Univ Warsaw, Heavy Ion Lab, Pasteura 5A, PL-02093 Warsaw, Poland..
    Sahin, E.
    INFN Lab Nazl Legnaro, Viale Univ 2, I-35020 Legnaro, Italy..
    Salsac, M-D
    Soderstrom, P-A
    Stefan, I.
    Inst Phys Nucl Orsay, F-91400 Orsay, France..
    Stezowski, O.
    Univ Lyon 1, CNRS, IN2P3, IPN Lyon, F-69622 Villeurbanne, France..
    Styczen, J.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland..
    Theisen, Ch.
    Univ Paris Saclay, CEA, Irfu, F-91191 Gif Sur Yvette, France..
    Toniolo, N.
    INFN Lab Nazl Legnaro, Viale Univ 2, I-35020 Legnaro, Italy..
    Ur, C. A.
    INFN Sez Padova, I-35131 Padua, Italy.;Univ Padua, Dipartimento Fis & Astron, I-35131 Padua, Italy..
    Wadsworth, R.
    Univ York, Dept Phys, York YO10 5DD, N Yorkshire, England..
    Wasilewska, B.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland..
    Wiens, A.
    Univ Cologne, Inst Kernphys, Zulpicher Str 77, D-50937 Cologne, Germany..
    Wood, J. L.
    Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA..
    Wrzosek-Lipska, K.
    Univ Warsaw, Heavy Ion Lab, Pasteura 5A, PL-02093 Warsaw, Poland..
    Zieblinski, M.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland..
    Quadrupole collectivity in Ca-42 from low-energy Coulomb excitation with AGATA2018In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 97, no 2, article id 024326Article in journal (Refereed)
    Abstract [en]

    ACoulomb-excitation experiment to study electromagnetic properties of Ca-42 was performed using a 170-MeV calcium beam from the TANDEM XPU facility at INFN Laboratori Nazionali di Legnaro. gamma rays from excited states in Ca-42 were measured with the AGATA spectrometer. The magnitudes and relative signs of ten E2 matrix elements coupling six low-lying states in Ca-42, including the diagonal E2 matrix elements of 2(1)(+) and 2(2)(+) states, were determined using the least-squares code GOSIA. The obtained set of reduced E2 matrix elements was analyzed using the quadrupole sum rule method and yielded overall quadrupole deformation for 0(1),(+)(2) and 2(1,2)(+) states, as well as triaxiality for 0(1,2)(+) states, establishing the coexistence of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in Ca-42. The experimental results were compared with the state-of-the-art large-scale shell-model and beyond-mean-field calculations, which reproduce well the general picture of shape coexistence in Ca-42.

  • 40. Herzan, A.
    et al.
    Juutinen, S.
    Auranen, K.
    Grahn, T.
    Greenlees, P. T.
    Hauschild, K.
    Jakobsson, Ulrika
    KTH, School of Engineering Sciences (SCI), Physics. University of Jyväskylä, Finland.
    Julin, R.
    Ketelhut, S.
    Leino, M.
    Lopez-Martens, A.
    Lonnroth, T.
    Nieminen, P.
    Nyman, M.
    Partanen, J.
    Peura, P.
    Rahkila, P.
    Ruotsalainen, P.
    Sandzelius, M.
    Saren, J.
    Scholey, C.
    Slotte, J. M. K.
    Sorri, J.
    Stolze, S.
    Uusitalo, J.
    Detailed spectroscopy of Bi-1952017In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 96, no 1, article id 014301Article in journal (Refereed)
    Abstract [en]

    An experiment focused on the study of shape coexistence and new high-spin structures in Bi-195 has been performed. The nucleus is in a transitional region of the bismuth isotope chain. A large number of new states have been found, resulting in a significant extension of the previously known level scheme. Several new collective structures have been identified. A strongly coupled rotational band built upon the 13/2(+) isomeric state was extended up to I-pi = (49/2(+)) and an energy of 5706 keV. The I-pi = 31/2(+) member of the pi i(13/2) band was also found to feed a new long-lived isomeric state with an excitation energy of 2616 keV and a spin and parity of I-pi = 29/2(+). The half-life of the 29/2+ isomeric state was determined to be 1.49(1) mu s. It decays via the emission of 457-keV E2 and 236-keV E1 transitions, respectively. A low-energy 46-keV E2 transition has been identified to depopulate the (29/(2-)) isomeric state, with a measured half-life of T-1/2 = 614(5) ns. This transition allows the excitation energy of the isomeric state to be determined as 2381 keV. The feeding patterns of both 29/2(+) and (29/2(-)) isomeric states have also been described. This is the first time collective structures have also been observed up to high spins and excitation energies in the neutron-deficient Bi-195 nucleus. Evidence for the manifestation of shape coexistence in Bi-195 is also discussed.

  • 41. Häfner, G.
    et al.
    Moschner, K.
    Blazhev, A.
    Boutachkov, P.
    Davies, P. J.
    Wadsworth, R.
    Ameil, F.
    Baba, H.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Dewald, M.
    Doornenbal, P.
    Faestermann, T.
    Gengelbach, A.
    Gerl, J.
    Gernhaüser, R.
    Go, S.
    Górska, M.
    Grawe, H.
    Gregor, E.
    Hotaka, H.
    Isobe, T.
    Jenkins, D. G.
    Jolie, J.
    Jung, H. S.
    Kojouharov, I.
    Kurz, N.
    Lewitowicz, M.
    Lorusso, G.
    Lozeva, R.
    Merchan, E.
    Naqvi, F.
    Nishibata, H.
    Nishimura, D.
    Nishimura, S.
    Pietralla, N.
    Schaffner, H.
    Söderström, P. -A
    Steiger, K.
    Sumikama, T.
    Taprogge, J.
    Thöle, P.
    Watanbe, H.
    Warr, N.
    Werner, V.
    Xu, Z. Y.
    Yagi, A.
    Yoshinaga, K.
    Zhu, Y.
    Properties of γ-decaying isomers in the Sn 100 region populated in fragmentation of a Xe 124 beam2019In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 100, no 2, article id 024302Article in journal (Refereed)
    Abstract [en]

    A systematic study was performed of microsecond γ-decaying isomers around Sn100 produced in a fragmentation reaction of a Xe124 beam at 345 MeV/u at the Radioactive Ion Beam Factory of the RIKEN Nishina Center in Saitama, Japan. Half-lives of isomeric states in that region were remeasured allowing us to improve the currently available experimental information. Reduced transition probabilities were deduced and compared to shell-model calculations in various model spaces. The recently reported low-energy transitions in Rh92 and Ag96 were remeasured with improved precision. Additionally, experimental information on isomeric ratios, including five new ones, were extracted and compared to a previous experimental study and the sharp cutoff model of fragmentation reaction.

  • 42.
    Juhasz, M. M.
    et al.
    Atomki, Bem Ter 18-C, H-4026 Debrecen, Hungary.;Univ Debrecen, Dept Phys, Egyet Ter 1, H-4032 Debrecen, Hungary..
    Aktas, Özge
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liu, Haichun
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Tech Univ Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany.;Univ Paris Saclay, CEA, IRFU, F-91191 Gif Sur Yvette, France..
    Zanetti, L.
    Tech Univ Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany..
    et al.,
    First spectroscopic study of V-63 at the N=40 island of inversion2021In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 103, no 6, article id 064308Article in journal (Refereed)
    Abstract [en]

    The low-lying level structure of V-63 was studied for the first time by the inelastic proton scattering and the proton knock-out reaction in inverse kinematics. The comparison of the newly observed gamma-ray transitions at 696(8) keV and 889(16) keV with our shell-model calculations using the Lenzi-Nowacki-Poves-Sieja interaction established two excited states proposed to be the first 11/2(-) and 9/2(-) levels. The (p, p') excitation cross sections were analyzed by the coupled channel formalism assuming pure quadrupole as well as quadrupole+hexadecapole deformations. This resulted in large deformation parameters placing V-63 in the island of inversion located below Ni-68.

  • 43. Kobyakov, D. N.
    et al.
    Pethick, C. J.
    KTH, Centres, Nordic Institute for Theoretical Physics NORDITA.
    Reddy, S.
    Schwenk, A.
    Dispersion and decay of collective modes in neutron star cores2017In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 96, no 2, article id 025805Article in journal (Refereed)
    Abstract [en]

    We calculate the frequencies of collective modes of neutrons, protons, and electrons in the outer core of neutron stars. The neutrons and protons are treated in a hydrodynamic approximation and the electrons are regarded as collisionless. The coupling of the nucleons to the electrons leads to Landau damping of the collective modes and to significant dispersion of the low-lying modes. We investigate the sensitivity of the mode frequencies to the strength of entrainment between neutrons and protons, which is not well characterized. The contribution of collective modes to the thermal conductivity is evaluated.

  • 44.
    Le Yang, Gao
    et al.
    Shandong Univ, Inst Space Sci, Sch Space Sci & Phys, Weihai 264209, Peoples R China..
    Qi, Bin
    Shandong Univ, Inst Space Sci, Sch Space Sci & Phys, Weihai 264209, Peoples R China..
    Wang, Xu Dong
    Shandong Univ, Inst Space Sci, Sch Space Sci & Phys, Weihai 264209, Peoples R China..
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Neutron-proton interaction in odd-odd nuclei from statistical analysis2022In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 106, no 2, article id 024325Article in journal (Refereed)
    Abstract [en]

    The statistical distribution and correlation relationship of the empirical neutron-proton (np) interaction are analyzed, whereby the interaction strengths are extracted from the binding energies using a known four-point formula. By comparing the correlations of the data and those from numerical simulations of the random number method, it is shown that an additional attractive np interaction persists between the last proton and last neutron in odd-odd nuclei. It provides evidence of the residual np interaction from statistical analysis. The adopted new analytical method might be a useful way to clarify the inherent correlation.

  • 45.
    Lewis, M. C.
    et al.
    Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England..
    Parr, E.
    Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England..
    Page, R. D.
    Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England..
    McPeake, C.
    Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England..
    Joss, D. T.
    Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England..
    Ali, F. A.
    Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England.;Univ Sulaimani, Coll Educ, Dept Phys, POB 334, Sulaimani, Kurdistan Regio, Iraq.;Univ Guelph, Dept Phys, Guelph, ON N1G 2W1, Canada..
    Auranen, K.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland.;Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA..
    Briscoe, A. D.
    Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England..
    Capponi, L.
    Univ West Scotland, Sch Engn & Comp, Paisley PA1 2BE, Renfrew, Scotland..
    Grahn, T.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland..
    Greenlees, P. T.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland..
    Henderson, J.
    Univ York, Dept Phys, York YO10 5DD, N Yorkshire, England.;Lawrence Livermore Natl Lab, 7000 East Ave, Livermore, CA 94550 USA..
    Herzan, A.
    Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England.;Slovak Acad Sci, Inst Phys, SK-84511 Bratislava, Slovakia..
    Jakobsson, Ulrika
    KTH, School of Engineering Sciences (SCI), Physics. Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland.
    Julin, R.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland..
    Juutinen, S.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland..
    Konki, J.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland.;CERN, CH-1211 Geneva 23, Switzerland..
    Labiche, M.
    STFC Daresbury Lab, Warrington WA4 4AD, Cheshire, England..
    Leino, M.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland..
    Mason, P. J. R.
    STFC Daresbury Lab, Warrington WA4 4AD, Cheshire, England..
    Nyman, M.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland.;IRMM, Retieseweg 111, B-2440 Geel, Belgium..
    O'Donnell, D.
    Univ West Scotland, Sch Engn & Comp, Paisley PA1 2BE, Renfrew, Scotland..
    Pakarinen, J.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland..
    Papadakis, P.
    Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England.;Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland..
    Partanen, J.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland..
    Peura, P.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland.;Univ Helsinki, Helsinki Inst Phys, FI-00014 Helsinki, Finland..
    Rahkila, P.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland..
    Revill, J. P.
    Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England..
    Ruotsalainen, P.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland..
    Sandzelius, M.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland..
    Saren, J.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland..
    Saygi, B.
    Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England.;Ege Univ, Fen Fak, Fizik Bolumu, TR-35100 Izmir, Turkey..
    Scholey, C.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland..
    Simpson, J.
    STFC Daresbury Lab, Warrington WA4 4AD, Cheshire, England..
    Smith, J. F.
    Univ West Scotland, Sch Engn & Comp, Paisley PA1 2BE, Renfrew, Scotland..
    Smolen, M.
    Univ West Scotland, Sch Engn & Comp, Paisley PA1 2BE, Renfrew, Scotland..
    Sorri, J.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland..
    Stolze, S.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland.;Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA..
    Thornthwaite, A.
    Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England..
    Uusitalo, J.
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland..
    Decay of a 19(-) isomeric state in Lu-1562018In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 98, no 2, article id 024302Article in journal (Refereed)
    Abstract [en]

    A multiparticle spin-trap isomeric state having a half-life of 179(4) ns and lying 2601 keV above the yrast 10(+) state in Lu-156 has been discovered. The Lu-156 nuclei were produced by bombarding isotopically enriched Cd-106 targets with beams of Ni-58 ions, separated in flight using the gas-filled separator RITU and their decays were measured using the GREAT spectrometer. Analysis of the main decay path that populates yrast states observed previously suggests a spin-parity assignment of 19(-) for the isomeric state, which is consistent with isomeric states identified in the N = 85 isotones. Comparison with other decay paths in Lu-156 indicates that the [pi h(11/)(2)(-1) circle times nu h(9/2)]10(+) state at the bottom of the yrast sequence is likely to be the a-decaying isomeric state, with the [pi h(11/)(2)(-1) circle times nu f(7/2)]9(+) state lying 62 keV above it. The relative ordering of the lowest-lying 9(+) and 10(+) states is inverted in Lu-156 compared with its odd-odd isotones.

  • 46.
    Linh, B. D.
    et al.
    VINATOM, Inst Nucl Sci & Technol, 179 Hoang Quoc, Hanoi, Vietnam..
    Gillibert, A.
    Univ Paris Saclay, IRFU, CEA, F-91191 Gif Sur Yvette, France..
    Liu, Haichun
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Univ Paris Saclay, IRFU, CEA, F-91191 Gif Sur Yvette, France.;Tech Univ Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany..
    Aktas, Onur
    KTH, School of Engineering Sciences (SCI), Physics.
    Zanetti, L.
    Tech Univ Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany..
    et al.,
    Investigation of the ground-state spin inversion in the neutron-rich Cl-47,Cl-49 isotopes2021In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 104, no 4, article id 044331Article in journal (Refereed)
    Abstract [en]

    A first gamma-ray study of Cl-47,Cl-49 spectroscopy was performed at the Radioactive Isotope Beam Factory with 50 Ar projectiles at 217 MeV/nucleon, impinging on the liquid hydrogen target of the MINOS device. Prompt deexcitation gamma rays were measured with the NaI(T1) array DALI2(+). Through the one-proton knockout reaction Ar-50(p, 2p), a spin assignment could be determined for the low-lying states of Cl-49 from the momentum distribution obtained with the SAMURAI spectrometer. A spin-parity J(pi) = 3/2(+) is deduced for the ground state of Cl-49, similar to the recently studied N = 32 isotope K-51. The evolution of the energy difference E(1/2(1)(+)) - E (3/2(1)(+)) is compared to state-of-the-art theoretical predictions.

  • 47.
    Litzinger, J.
    et al.
    Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany..
    Blazhev, A.
    Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany..
    Dewald, A.
    Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany..
    Didierjean, F.
    Univ Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France..
    Duchene, G.
    Univ Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France..
    Fransen, C.
    Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany..
    Lozeva, R.
    Univ Paris Saclay, CSNSM, CNRS IN2P3, Orsay Campus, FR-91405 Orsay, France..
    Verney, D.
    CNRS IN2P3, Inst Phys Nucl, F-91405 Orsay, France.;Univ Paris 11, F-91405 Orsay, France..
    de Angelis, G.
    Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy..
    Bazzacco, D.
    Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy.;Univ Padua, I-35131 Padua, Italy..
    Birkenbach, B.
    Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany..
    Bottoni, S.
    Univ Milan, Dipartimento Fis, I-20133 Milan, Italy.;Ist Nazl Fis Nucl, Sez Milano, Via Celoria 16, I-20133 Milan, Italy..
    Bracco, A.
    Univ Milan, Dipartimento Fis, I-20133 Milan, Italy.;Ist Nazl Fis Nucl, Sez Milano, Via Celoria 16, I-20133 Milan, Italy..
    Braunroth, T.
    Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany..
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Corradi, L.
    Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy..
    Crespi, F. C. L.
    Univ Milan, Dipartimento Fis, I-20133 Milan, Italy.;Ist Nazl Fis Nucl, Sez Milano, Via Celoria 16, I-20133 Milan, Italy..
    Desesquelles, P.
    Ctr Spectrometrie Nucl & Spectrometrie Masse CSNS, CNRS IN2P3, Orsay Campus, F-91405 Orsay, France.;Univ Paris 11, Orsay Campus, F-91405 Orsay, France..
    Eberth, J.
    Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany..
    Ellinger, E.
    Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany..
    Farnea, E.
    Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy.;Univ Padua, I-35131 Padua, Italy..
    Fioretto, E.
    Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy..
    Gernhaeuser, R.
    Tech Univ Munich, Phys Dept E12, D-85748 Garching, Germany..
    Goasduff, A.
    Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy..
    Gorgen, A.
    Ctr CEA Saclay, Inst Rech Fondamentales Univers IRFU, CEA DSM, F-91191 Gif Sur Yvette, France.;Univ Oslo, Dept Phys, POB 1048 Blindern, N-0316 Oslo, Norway..
    Gottardo, A.
    Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy..
    Grebosz, J.
    Polish Acad Sci, Henry Niewodniczatiski Inst Nucl Phys, Ul Radzikowskiego 152, PL-31342 Krakow, Poland..
    Hackstein, M.
    Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany..
    Hess, H.
    Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany..
    Ibrahim, F.
    CNRS IN2P3, Inst Phys Nucl, F-91405 Orsay, France.;Univ Paris 11, F-91405 Orsay, France..
    Jolie, J.
    Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany..
    Jungclaus, A.
    CSIC, Inst Estruct Mat, Serrano 119, E-28006 Madrid, Spain..
    Kolos, K.
    CNRS IN2P3, Inst Phys Nucl, F-91405 Orsay, France.;Univ Paris 11, F-91405 Orsay, France..
    Korten, W.
    Ctr CEA Saclay, Inst Rech Fondamentales Univers IRFU, CEA DSM, F-91191 Gif Sur Yvette, France..
    Leoni, S.
    Univ Milan, Dipartimento Fis, I-20133 Milan, Italy.;Ist Nazl Fis Nucl, Sez Milano, Via Celoria 16, I-20133 Milan, Italy..
    Lunardi, S.
    Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy.;Univ Padua, I-35131 Padua, Italy..
    Maj, A.
    Menegazzo, R.
    Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy..
    Mengoni, D.
    Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy.;Univ Padua, I-35131 Padua, Italy.;Univ West Scotland, Nucl Phys Res Grp, High St, Paisley PA1 2BE, Renfrew, Scotland..
    Michelagnoli, C.
    Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy.;GANIL, CEA DSM CNRS IN2P3, BP 55027, F-14076 Caen 5, France..
    Mijatovic, T.
    Ruder Bakovie Inst, HR-10002 Zagreb, Croatia..
    Million, B.
    Ist Nazl Fis Nucl, Sez Milano, I-20133 Milan, Italy..
    Moeller, O.
    Tech Univ Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany..
    Modamio, V.
    Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy..
    Montagnoli, G.
    Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy.;Univ Padua, I-35131 Padua, Italy..
    Montanari, D.
    Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy.;Univ Padua, I-35131 Padua, Italy..
    Morales, A. I.
    Univ Milan, Dipartimento Fis, I-20133 Milan, Italy.;Ist Nazl Fis Nucl, Sez Milano, Via Celoria 16, I-20133 Milan, Italy..
    Napoli, D. R.
    Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy..
    Niikura, M.
    CNRS IN2P3, Inst Phys Nucl, F-91405 Orsay, France.;Univ Paris 11, F-91405 Orsay, France..
    Pietralla, N.
    Tech Univ Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany..
    Pollarolo, G.
    Univ Turin, Dipartimento Fis Teor, I-10125 Turin, Italy.;Ist Nazl Fis Nucl, I-10125 Turin, Italy..
    Pullia, A.
    Univ Milan, Dipartimento Fis, I-20133 Milan, Italy.;Ist Nazl Fis Nucl, Sez Milano, Via Celoria 16, I-20133 Milan, Italy..
    Quintana, B.
    Univ Salamanca, Lab Radiaciones Ionizantes, E-37008 Salamanca, Spain..
    Recchia, F.
    Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy.;Univ Padua, I-35131 Padua, Italy..
    Reiter, P.
    Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany..
    Rosso, D.
    Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy..
    Sahin, E.
    Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy..
    Salsac, M. D.
    Ctr CEA Saclay, Inst Rech Fondamentales Univers IRFU, CEA DSM, F-91191 Gif Sur Yvette, France..
    Scarlassara, F.
    Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy.;Univ Padua, I-35131 Padua, Italy..
    Soderstroem, P. -A
    Stefanini, A. M.
    Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy..
    Stezowski, O.
    Univ Lyon, Univ Lyon 1, IN2P3 CNRS, F-69622 Villeurbanne, France..
    Szilner, S.
    Ruder Bakovie Inst, HR-10002 Zagreb, Croatia..
    Theisen, Ch.
    Ctr CEA Saclay, Inst Rech Fondamentales Univers IRFU, CEA DSM, F-91191 Gif Sur Yvette, France..
    Valiente-Dobon, J. J.
    Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy..
    Vandone, V.
    Univ Milan, Dipartimento Fis, I-20133 Milan, Italy.;Ist Nazl Fis Nucl, Sez Milano, Via Celoria 16, I-20133 Milan, Italy..
    Vogt, A.
    Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany..
    Transition probabilities in neutron-rich Se-80,Se-82 and the role of the nu g(9/2) orbital2018In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 97, no 4, article id 044323Article in journal (Refereed)
    Abstract [en]

    Transition probabilities of intermediate-spin yrast and non-yrast excitations in Se-80,Se-82 were investigated in a recoil distance Doppler-shift (RDDS) experiment performed at the Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro. The Cologne Plunger device for deep inelastic scattering was used for the RDDS technique and was combined with the AGATA Demonstrator array for the gamma-ray detection and coupled to the PRISMA magnetic spectrometer for an event-by-event particle identification. In Se-80, the level lifetimes of the yrast (6(1)(+)) and (8(1)(+)) states and of a non-yrast band feeding the yrast 4(1)(+) state are determined. A spin and parity assignment of the head of this sideband is discussed based on the experimental results and supported by large-scale shell-model calculations. In Se-82, the level lifetimes of the yrast 6(1)(+) state and the yrare 4(2)(+) state and lifetime limits of the yrast (10(1)(+)) state and of the 5(1)(-) state are determined. Although the experimental results contain large uncertainties, they are interpreted with care in terms of large-scale shell-model calculations using the effective interactions JUN45 and jj44b. The excited states' wave functions are investigated and discussed with respect to the role of the neutron g(9/2) orbital.

  • 48. Liu, X.
    et al.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics.
    Wyss, Ramon Alexander
    KTH, School of Engineering Sciences (SCI), Physics.
    Aktas, Özge
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ertoprak, Aysegul
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Zhang, Wei
    KTH, School of Engineering Sciences (SCI), Physics.
    Nyberg, Ayse
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. Royal Inst Technol, Dept Phys, S-10405 Stockholm, Sweden..
    Back, Tove
    KTH, School of Engineering Sciences (SCI), Physics.
    Zielinska, M.
    Univ Paris Saclay, CEA, Itfu, F-91191 Gif Sur Yvette, France..
    Evidence for enhanced neutron-proton correlations from the level structure of the N = Z+1 nucleus Tc-87(43)442021In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 104, no 2, article id L021302Article in journal (Refereed)
    Abstract [en]

    The low-lying excited states in the neutron-deficient N = Z + 1 nucleus (87)(43)Tcc(44) have been studied via the fusion-evaporation reaction Fe-54(Ar-36, 2n1p)Tc-87 at the Grand Accelerateur National d'Ions Lourds (GANIL), France. The AGATA spectrometer was used in conjunction with the auxiliary NEDA, Neutron Wall, and DIAMANT detector arrays to measure coincident prompt gamma rays, neutrons, and charged particles emitted in the reaction. A level scheme of Tc-87 from the (9/2(g.s.)(+)) state to the (33/2(1)(+)) state was established based on six mutually coincident gamma-ray transitions. The constructed level structure exhibits a rotational behavior with a sharp backbending at (h) over bar omega approximate to 0.50 MeV. A decrease in alignment frequency and increase in alignment sharpness in the odd-mass isotonic chains around N = 44 is proposed as an effect of the enhanced isoscalar neutron-proton interactions in odd-mass nuclei when approaching the N = Z line.

  • 49.
    Liu, Xiaoyu
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; University of Chinese Academy of Sciences, Beijing, China.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon Alexander
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Aktas, Özge
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ertoprak, Aysegul
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. Istanbul Univ, Fac Sci, Dept Phys, TR-34134 Istanbul, Turkey..
    Zhang, Wei
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Nyberg, Ayse Ataç
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Zielinska, M.
    Univ Paris Saclay, CEA, IRFU, F-91191 Gif Sur Yvette, France..
    et al.,
    Evidence for spherical-oblate shape coexistence in Tc-872022In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 106, no 3, article id 034304Article in journal (Refereed)
    Abstract [en]

    Excited states in the neutron-deficient nucleus Tc-87 have been studied via the fusion-evaporation reaction 54Fe(36Ar, 2n1p) Tc-87 at 115 MeV beam energy. The AGATA gamma-ray spectrometer coupled to the DIAMANT, NEDA, and Neutron Wall detector arrays for light-particle detection was used to measure the prompt coincidence of gamma rays and light particles. Six transitions from the deexcitation of excited states belonging to a new band in Tc-87 were identified by comparing gamma-ray intensities in the spectra gated under different reaction channel selection conditions. The constructed level structure was compared with the shell model and total Routhian surface calculations. The results indicate that the new band structure in 87Tc is built on a spherical configuration, which is different from that assigned to the previously identified oblate yrast rotational band.

  • 50. Lv, B. F.
    et al.
    Petrache, C. M.
    Astier, A.
    Dupont, E.
    Lopez-Martens, A.
    Greenlees, P. T.
    Badran, H.
    Calverley, T.
    Cox, D. M.
    Grahn, T.
    Hilton, J.
    Julin, R.
    Juutinen, S.
    Konki, J.
    Leino, M.
    Pakarinen, J.
    Papadakis, P.
    Partanen, J.
    Rahkila, P.
    Sandzelius, M.
    Saren, J.
    Scholey, C.
    Sorri, J.
    Stolze, S.
    Uusitalo, J.
    Herzán, A.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Ertoprak, Aysegul
    KTH, School of Engineering Sciences (SCI), Physics.
    Liu, H.
    Guo, S.
    Liu, M. L.
    Qiang, Y. H.
    Wang, J. G.
    Zhou, X. H.
    Kuti, I.
    Timár, J.
    Tucholski, A.
    Srebrny, J.
    Andreoiu, C.
    Evolution from γ -soft to stable triaxiality in Nd 136 as a prerequisite of chirality2018In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 98, no 4, article id 044304Article in journal (Refereed)
    Abstract [en]

    The level structure of Nd136 has been investigated using the Mo100(Ar40,4n) reaction and the JUROGAM II+RITU+GREAT setup. The level scheme has been extended significantly. Many new bands have been identified both at low and high spin, among which are five nearly degenerate bands interpreted as chiral partners. Excitation energies, spins, and parities of the previously known bands are revised and firmly established, and some previously known bands have been revised. Configurations are assigned to the observed bands based on cranked Nilsson-Strutinsky calculations. The band structure of Nd136 is now clarified and the various types of single-particle and collective excitations are well understood.

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