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  • 1. Aabou, 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.
    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.,
    ZZ -> l(+)l(-)l '(+)l '(-) cross-section measurements and search for anomalous triple gauge couplings in 13 TeV pp collisions with the ATLAS detector2018In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490XArticle in journal (Refereed)
    Abstract [en]

    Measurements of ZZ production in the l(+)l(-)l'(+)l'(-) channel in proton-proton collisions at 13 TeV center-of-mass energy at the Large Hadron Collider are presented. The data correspond to 36.1 fb(-1) of collisions collected by the ATLAS experiment in 2015 and 2016. Here l and l ' stand for electrons or muons. Integrated and differential ZZ -> l(+)l(-)l'(+)l'(-) cross sections with Z -> l(+)l(-) candidate masses in the range of 66 GeV to 116 GeV are measured in a fiducial phase space corresponding to the detector acceptance and corrected for detector effects. The differential cross sections are presented in bins of twenty observables, including several that describe the jet activity. The integrated cross section is also extrapolated to a total phase space and to all standard model decays of Z bosons with mass between 66 GeV and 116 GeV, resulting in a value of 17.3 +/- 0.9 [+/- 0.6(start) +/- 0.5 (syst) +/- 0.6 (lumi)] pb. The measurements are found to be in good agreement with the standard model. A search for neutral triple gauge couplings is performed using the transverse momentum distribution of the leading Z boson candidate. No evidence for such couplings is found and exclusion limits are set on their parameters.

  • 2. 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.,
    Search for flavor-changing neutral currents in top quark decays t -> Hc and t -> Hu in multilepton final states in proton-proton collisions at root s=13 TeV with the ATLAS detector2018In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 98, no 3, article id 032002Article in journal (Refereed)
    Abstract [en]

    Flavor-changing neutral currents are not present in the Standard Model at tree level and are suppressed in loop processes by the unitarity of the Cabibbo-Kobayashi-Maskawa matrix; the corresponding rates for top quark decay processes are experimentally unobservable. Extensions of the Standard Model can generate new flavor-changing neutral current processes, leading to signals which, if observed, would be unambiguous evidence of new interactions. A data set conesponding to an integrated luminosity of 36.1 fb(-1) of pp collisions at a center-of-mass energy of root s = 13 TeV recorded with the ATLAS detector at the Large Hadron Collider is used to search for top quarks decaying to up or charm quarks with the emission of a Higgs boson, with subsequent Higgs boson decay to final states with at least one electron or muon. No signal is observed and limits on the branching fractions B(t -> Hc) < 0.16% and B(t -> Hu) < 0.19% at 95% confidence level are obtained (with expected limits of 0.15% in both cases).

  • 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.,
    Evidence for the associated production of the Higgs boson and a top quark pair with the ATLAS detector2018In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490XArticle in journal (Refereed)
    Abstract [en]

    A search for the associated production of the Higgs boson with a top quark pair ((tt) over barH) is reported. The search is performed in multilepton final states using a data set corresponding to an integrated luminosity of 36.1 fb(-1) of proton-proton collision data recorded by the ATLAS experiment at a center-of-mass energy root s = 13 TeV at the Large Hadron Collider. Higgs boson decays to WW*, tau tau, and ZZ* are targeted. Seven final states, categorized by the number and flavor of charged-lepton candidates, are examined for the presence of the Standard Model Higgs boson with a mass of 125 GeVand a pair of top quarks. An excess of events over the expected background from Standard Model processes is found with an observed significance of 4.1 standard deviations, compared to an expectation of 2.8 standard deviations. The best fit for the (tt) over barH production cross section is sot (tt) over barH) = 790(-210)(+230) fb, in agreement with the Standard Model prediction of 507(-50)(+35) fb. The combination of this result with other t <overline> tH searches from the ATLAS experiment using the Higgs boson decay modes to b (b) over bar, gamma gamma and ZZ* -> 4l, has an observed significance of 4.2 standard deviations, compared to an expectation of 3.8 standard deviations. This provides evidence for the (tt) over barH production mode.

  • 4. 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 long-range multiparticle azimuthal correlations with the subevent cumulant method in pp and p plus Pb collisions with the ATLAS detector at the CERN Large Hadron Collider2018In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490XArticle in journal (Refereed)
    Abstract [en]

    A detailed study of multiparticle azimuthal correlations is presented using pp data at root s = 5.02 and 13 TeV, and p+Pb data at root s(NN) = 5.02 TeV, recorded with the ATLAS detector at the CERN Large Hadron Collider. The azimuthal correlations are probed using four-particle cumulants c(n){4} and flow coefficients v(n){4} = (-c(n){4})(1/4) for n = 2 and 3, with the goal of extracting long-range multiparticle azimuthal correlation signals and suppressing the short-range correlations. The values of c(n){4} are obtained as a function of the average number of charged particles per event, < N-ch >, using the recently proposed two-subevent and three-subevent cumulant methods, and compared with results obtained with the standard cumulant method. The standard method is found to be strongly biased by short-range correlations, which originate mostly from jetswith a positive contribution to c(n){4}. The threesubevent method, on the other hand, is found to be least sensitive to short-range correlations. The three-subevent method gives a negative c(2){4}, and therefore a well-defined v(2){4}, nearly independent of < N-ch >, which implies that the long-range multiparticle azimuthal correlations persist to events with low multiplicity. Furthermore, v(2){4} is found to be smaller than the v(2){2} measured using the two-particle correlation method, as expected for long-range collective behavior. Finally, the measured values of v(2){4} and v(2){2} are used to estimate the number of sources relevant for the initial eccentricity in the collision geometry. The results based on the subevent cumulant technique provide direct evidence, in small collision systems, for a long-range collectivity involving many particles distributed across a broad rapidity interval.

  • 5. 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.
    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.,
    Measurements of long-range azimuthal anisotropies and associated Fourier coefficients for pp collisions at root s=5.02 and 13 TeV and p plus Pb collisions at root(NN)-N-s=5.02 TeV with the ATLAS detector2017In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 96, no 2, article id 024908Article in journal (Refereed)
    Abstract [en]

    ATLAS measurements of two-particle correlations are presented for root s = 5.02 and 13 TeV pp collisions and for root(NN)-N-s = 5.02 TeV p + Pb collisions at the LHC. The correlation functions are measured as a function of relative azimuthal angle Delta phi, and pseudorapidity separation Delta eta, using charged particles detected within the pseudorapidity interval |eta| < 2.5. Azimuthal modulation in the long-range component of the correlation function, with | Delta eta| > 2, is studied using a template fitting procedure to remove a "back-to-back" contribution to the correlation function that primarily arises from hard-scattering processes. In addition to the elliptic, cos(2 Delta phi), modulation observed in a previous measurement, the pp correlation functions exhibit significant cos(3 Delta phi) and cos(4 Lambda phi) modulation. The Fourier coefficients v(n),(n) associated with the cos (n Lambda phi) modulation of the correlation functions for n = 2-4 are measured as a function of charged-particle multiplicity and charged-particle transverse momentum. The Fourier coefficients are observed to be compatible with cos(n phi) modulation of per-event singleparticle azimuthal angle distributions. The single-particle Fourier coefficients vn are measured as a function of charged-particle multiplicity, and charged-particle transverse momentum for n = 2-4. The integrated luminosities used in this analysis are, 64 nb(-1) for the root s = 13 TeV pp data, 170 nb(-1) for the root s = 5.02 TeV pp data, and 28 nb(-1) for the root(NN)-N-s = 5.02 TeV p + Pb data.

  • 6. Aad, G.
    et al.
    Jovicevic, Jelena
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Kuwertz, Emma
    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.
    Morley, Anthony
    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.
    Measurement of event-plane correlations in root s(NN)=2.76 TeV lead-lead collisions with the ATLAS detector2014In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 90, no 2, p. 024905-Article in journal (Refereed)
    Abstract [en]

    A measurement of event-plane correlations involving two or three event planes of different order is presented as a function of centrality for 7 mu b(-1) Pb + Pb collision data at v root s(NN) = 2.76 TeV, recorded by the ATLAS experiment at the Large Hadron Collider. Fourteen correlators are measured using a standard event-plane method and a scalar-product method, and the latter method is found to give a systematically larger correlation signal. Several different trends in the centrality dependence of these correlators are observed. These trends are not reproduced by predictions based on the Glauber model, which includes only the correlations from the collision geometry in the initial state. Calculations that include the final-state collective dynamics are able to describe qualitatively, and in some cases also quantitatively, the centrality dependence of the measured correlators. These observations suggest that both the fluctuations in the initial geometry and the nonlinear mixing between different harmonics in the final state are important for creating these correlations in momentum space.

  • 7. Aad, G.
    et al.
    Jovicevic, Jelena
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Kuwertz, Emma
    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.
    Morley, Anthony
    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.,
    Centrality, rapidity, and transverse momentum dependence of isolated prompt photon production in lead-lead collisions at root S-NN=2.76 TeV measured with the ATLAS detector2016In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 93, no 3, article id 034914Article in journal (Refereed)
    Abstract [en]

    Prompt photon production in root S-NN = 2.76-TeV Pb + Pb collisions has been measured by the ATLAS experiment at the Large Hadron Collider using data collected in 2011 with an integrated luminosity of 0.14 nb(-1). Inclusive photon yields, scaled by the mean nuclear thickness function, are presented as a function of collision centrality and transverse momentum in two pseudorapidity intervals, vertical bar eta vertical bar < 1.37 and 1.52 <= vertical bar eta vertical bar < 2.37. The scaled yields in the two pseudorapidity intervals, as well as the ratios of the forward yields to those at midrapidity, are compared to the expectations from next-to-leading-order perturbative QCD (pQCD) calculations. The measured cross sections agree well with the predictions for proton-proton collisions within statistical and systematic uncertainties. Both the yields and the ratios are also compared to two other pQCD calculations, one which uses the isospin content appropriate to colliding lead nuclei and another which includes nuclear modifications to the nucleon parton distribution functions.

  • 8. Aad, G
    et al.
    Jovicevic, Jelena
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Kuwertz, Emma
    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.
    Morley, Anthony
    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 differential J/psi production cross sections and forward-backward ratios in p plus Pb collisions with the ATLAS detector2015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 92, no 3, article id 034904Article in journal (Refereed)
    Abstract [en]

    Measurements of differential cross sections for J/psi production in p + Pb collisions at root S-NN= 5.02 TeV at the CERN Large Hadron Collider with the ATLAS detector are presented. The data set used corresponds to an integrated luminosity of 28.1 nb(-1). The J/psi mesons are reconstructed in the dimuon decay channel over the transverse momentum range 8 < PT < 30 GeV and over the center-of-mass rapidity range -2.87 < y* < 1.94. Prompt J/psi are separated from J/psi resulting from b-hadron decays through an analysis of the distance between the J/psi decay vertex and the event primary vertex. The differential cross section for production of nonprompt J/psi is compared to a FONLL calculation that does not include nuclear effects. Forward-backward production ratios are presented and compared to theoretical predictions. These results complement previously published results by covering a region of higher transverse momentum and more central rapidity. They thus constrain the kinematic dependence of nuclear modifications of charmonium and b-quark production in p + Pb collisions.

  • 9. Aad, G.
    et al.
    Jovicevic, Jelena
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Kuwertz, Emma
    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.
    Morley, Anthony
    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 long-range pseudorapidity correlations and azimuthal harmonics in root s(NN)=5.02 TeV proton-lead collisions with the ATLAS detector2014In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 90, no 4, p. 044906-Article in journal (Refereed)
    Abstract [en]

    Measurements of two-particle correlation functions and the first five azimuthal harmonics, v(1) to v(5), are presented, using 28 nb(-1) of p + Pb collisions at a nucleon-nucleon center-of-mass energy of root s(NN) = 5.02 TeV measured with the ATLAS detector at the LHC. Significant long-range "ridgelike" correlations are observed for pairs with small relative azimuthal angle (|Delta phi| < pi/3) and back-to-back pairs (|Delta phi| > 2 pi/3) over the transverse momentum range 0.4 < p(T) < 12 GeV and in different intervals of event activity. The event activity is defined by either the number of reconstructed tracks or the total transverse energy on the Pb-fragmentation side. The azimuthal structure of such long-range correlations is Fourier decomposed to obtain the harmonics v(n) as a function of p(T) and event activity. The extracted v(n) values for n = 2 to 5 decrease with n. The v(2) and v(3) values are found to be positive in the measured p(T) range. The v(1) is also measured as a function of p(T) and is observed to change sign around p(T) approximate to 1.5-2.0 GeV and then increase to about 0.1 for pT > 4 GeV. The v(2)(p(T)), v(3)(p(T)), and v(4)(p(T)) are compared to the v(n) coefficients in Pb + Pb collisions at root s(NN) = 2.76 TeV with similar event multiplicities. Reasonable agreement is observed after accounting for the difference in the average p(T) of particles produced in the two collision systems.

  • 10. Aad, G.
    et al.
    Jovicevic, Jelena
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Kuwertz, Emma
    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.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Zwalinski, L.
    et al.,
    Measurement of the azimuthal anisotropy for charged particle production in root s(NN)=2.76 TeV lead-lead collisions with the ATLAS detector2012In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 86, no 1, p. 014907-Article in journal (Refereed)
    Abstract [en]

    Differential measurements of charged particle azimuthal anisotropy are presented for lead-lead collisions at root sNN = 2.76 TeV with the ATLAS detector at the LHC, based on an integrated luminosity of approximately 8 mu b(-1). This anisotropy is characterized via a Fourier expansion of the distribution of charged particles in azimuthal angle relative to the reaction plane, with the coefficients v(n) denoting the magnitude of the anisotropy. Significant v(2)-v(6) values are obtained as a function of transverse momentum (0.5 < p(T) < 20 GeV), pseudorapidity (|eta| < 2.5), and centrality using an event plane method. The v(n) values for n >= 3 are found to vary weakly with both eta and centrality, and their p(T) dependencies are found to follow an approximate scaling relation, v(n)(1/n)(p(T)) proportional to v(2)(1/2)(p(T)), except in the top 5% most central collisions. A Fourier analysis of the charged particle pair distribution in relative azimuthal angle (Delta phi = phi(a)-phi(b)) is performed to extract the coefficients v(n,n) = < cos n Delta phi >. For pairs of charged particles with a large pseudorapidity gap (|Delta eta = eta(a) - eta(b)| > 2) and one particle with p(T) < 3 GeV, the v(2,2)-v(6,6) values are found to factorize as v(n,n)(p(T)(a), p(T)(b)) approximate to v(n) (p(T)(a))v(n)(p(T)(b)) in central and midcentral events. Such factorization suggests that these values of v(2,2)-v(6,6) are primarily attributable to the response of the created matter to the fluctuations in the geometry of the initial state. A detailed study shows that the v(1,1)(p(T)(a), p(T)(b)) data are consistent with the combined contributions from a rapidity-even v(1) and global momentum conservation. A two-component fit is used to extract the v(1) contribution. The extracted v(1) isobserved to cross zero at pT approximate to 1.0 GeV, reaches a maximum at 4-5 GeV with a value comparable to that for v(3), and decreases at higher p(T).

  • 11. Aad, G
    et al.
    Lund-Jensen, Bengt
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Morley, Anthony
    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 the correlation between flow harmonics of different order in lead-lead collisions at root S-NN=2.76 TeV with the ATLAS detector2015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 92, no 3, article id 034903Article in journal (Refereed)
    Abstract [en]

    Measurements of differential cross sections for J/psi production in p + Pb collisions at root S-NN= 5.02 TeV at the CERN Large Hadron Collider with the ATLAS detector are presented. The data set used corresponds to an integrated luminosity of 28.1 nb(-1). The J/psi mesons are reconstructed in the dimuon decay channel over the transverse momentum range 8 < PT < 30 GeV and over the center-of-mass rapidity range -2.87 < y* < 1.94. Prompt J/psi are separated from J/psi resulting from b-hadron decays through an analysis of the distance between the J/psi decay vertex and the event primary vertex. The differential cross section for production of nonprompt J/psi is compared to a FONLL calculation that does not include nuclear effects. Forward-backward production ratios are presented and compared to theoretical predictions. These results complement previously published results by covering a region of higher transverse momentum and more central rapidity. They thus constrain the kinematic dependence of nuclear modifications of charmonium and b-quark production in p + Pb collisions.

  • 12. Aad, G
    et al.
    Lund-Jensen, Bengt
    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.
    et al.,
    Z boson production in p plus Pb collisions at root S-NN=5.02 TeV measured with the ATLAS detector2015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 92, no 4, article id 044915Article in journal (Refereed)
    Abstract [en]

    The ATLAS Collaboration measures the inclusive production of Z bosons via their decays into electron and muon pairs in p + Pb collisions at root S-NN = 5.02 TeV at the Large Hadron Collider. The measurements are made using data corresponding to integrated luminosities of 29.4 and 28.1 nb(-1) for Z -> ee and Z -> mu mu, respectively. The results from the two channels are consistent and combined to obtain a cross section times the Z -> ll branching ratio, integrated over the rapidity region vertical bar y(Z)*vertical bar < 3.5, of 139.8 +/- 4.8 (statistical) +/- 6.2 (systematic) +/- 3.8 (luminosity) nb. Differential cross sections are presented as functions of the Z boson rapidity and transverse momentum and compared with models based on parton distributions both with and without nuclear corrections. The centrality dependence of Z boson production in p + Pb collisions is measured and analyzed within the framework of a standard Glauber model and the model's extension for fluctuations of the underlying nucleon-nucleon scattering cross section.

  • 13. Algora, A.
    et al.
    de Angelis, G.
    Brandolini, F.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Menegazzo, R.
    Thomas, H. G.
    Ur, C. A.
    et al,
    Pronounced shape change induced by quasiparticle alignment2000In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 6103, no 3Article in journal (Refereed)
    Abstract [en]

    Mean lifetimes of high-spin states of Kr-74 have been determined using the Doppler-shift attenuation method. The high-spin states were studied using the Ca-40(Ca-40, alpha 2p) reaction at a beam energy of 160 MeV with the GASP gamma-ray spectrometer. The ground-state band and negative parity side band show the presence of three different configurations in terms of transitional quadrupole deformations. A dramatic shape change was found along the ground-state band after the S-band crossing. The deduced quadrupole deformation changes are well reproduced by cranked Woods-Saxon Strutinsky calculations.

  • 14. Al-Khatib, A.
    et al.
    Singh, A. K.
    Hubel, H.
    Bringel, P.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Redon, N.
    et al,
    Competition between collective and noncollective excitation modes at high spin in Ba-1242006In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 74, no 1Article in journal (Refereed)
    Abstract [en]

    High-spin states in Ba-124 were investigated in two experiments using the Ni-64(Ni-64, 4n)Ba-124 reaction at three different beam energies. In-beam gamma-ray coincidences were measured with the Euroball and Gammasphere detector arrays. In the experiment with Euroball, the CsI detector array Diamant was employed to discriminate against charged-particle channels. Six new rotational bands were observed in Ba-124, and previously known bands were extended to higher spins. One of the bands shows a transition from collective to noncollective behavior at high spins. Configuration assignments are suggested on the basis of comparison with cranked shell model and cranked Nilsson-Strutinsky calculations.

  • 15. Almosly, W.
    et al.
    Carlsson, B. G.
    Dobaczewski, J.
    Suhonen, J.
    Toivanen, J.
    Vesely, P.
    Ydrefors, Emanuel
    KTH.
    Charged-current neutrino and antineutrino scattering off Cd-116 described by Skyrme forces2014In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 89, no 2, p. 024308-Article in journal (Refereed)
    Abstract [en]

    We perform calculations of the cross sections for charged-current neutrino and antineutrino scattering off Cd-116 using ten different Skyrme interactions, at energies typical of supernova neutrinos. We use the quasiparticle random-phase approximation in its charged-changing mode (pnQRPA) to construct the required nuclear wave functions for the participant initial and final states. We compare the results of these calculations with the results of calculations based on the Bonn one-boson-exchange potential. The response of Cd-116 to supernova neutrinos is calculated by folding the obtained cross sections with suitably parametrized Fermi-Dirac distributions of the electron-neutrino and electron-antineutrino energies.

  • 16.
    Andgren, Karin
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Bäck, Torbjörn
    KTH, School of Engineering Sciences (SCI), Physics.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    gamma-ray spectroscopy of At-1972008In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 78, no 4, p. 044328-1-044328-8Article in journal (Refereed)
    Abstract [en]

    Excited states of the extremely neutron-deficient nucleus At-197 have been studied in an in-beam experiment using the fusion-evaporation reaction Sn-118(Kr-82,p2n)At-197. gamma rays belonging to At-197 feeding the I-pi=(9/2(-)) ground state, as well as gamma rays feeding the 311-keV I-pi=(13/2(+)) isomer, decaying via the emission of gamma rays, and the 52-keV I-pi=(1/2(+)) alpha-decaying isomer have been identified using the recoil-alpha-decay tagging technique. Total Routhian surface calculations predict a near-spherical shape for the (9/2(-)) ground state and oblate shapes with beta(2) around -0.2 for the (1/2(+)) and the (13/2(+)) states. These predictions agree with our experimental findings.

  • 17.
    Andgren, Karin
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    et al.,
    Excited states in the neutron-deficient nuclei Rn-197,Rn-199,Rn-2012008In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 77, no 5, p. 054303-1-054303-7Article in journal (Refereed)
    Abstract [en]

    Excited states of the extremely neutron-deficient radon isotopes with N = 111, 113, 115 have been studied for the first time in a series of in-beam experiments performed at the Accelerator Laboratory of the University of Jyvaskyla. The reactions used were: Sn-118(Kr-82, 3n)Rn-197, Sn-120(Kr-82, 3n)Rn-199, Sm-150(Cr-52, 3n)Rn-199, and Sn-122(Kr-82, 3n)Rn-201. The gamma rays emitted from excited states in the different isotopes were identified using the recoil-alpha-decay tagging technique. The estimated cross section for the production of Rn-197(m) was 7(3) nb, which is the lowest cross section reported so far for an in-beam study. The energies of the (17/2(+)) levels built on the isomeric (13/2(+)) states in Rn-197,Rn-199,Rn-201 indicate a transition from an anharmonic vibrational structure toward a rotational structure at low spins for these nuclei. However, the transition is not as sharp as predicted by theory.

  • 18.
    Andgren, Karin
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Ganioglu, Ela
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics.
    et al.,
    Low-spin collective behavior in the transitional nuclei Mo-86,Mo-882007In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 76, no 1, p. 014307-1-014307-9Article in journal (Refereed)
    Abstract [en]

    Low-spin structures in Mo-86,Mo-88 were populated using the Ni-58(Ar-36, x alpha yp) heavy-ion fusion-evaporation reaction at a beam energy of 111 MeV. Charged particles and gamma rays were emitted in the reactions and detected by the DIAMANT CsI ball and the EXOGAM Ge array, respectively. In addition to the previously reported low-to-medium spin states in these nuclei, new low-spin structures were observed. Angular correlation and linear polarization measurements were performed in order to unambiguously determine the spins and parities of intensely populated states in Mo-88. Quasiparticle Random Phase Approximation (QRPA) calculations were performed for the first and second excited 2(+) states in Mo-86 and Mo-88. The results are in qualitative agreement with the experimental results, supporting a collective interpretation of the low-spin states for these transitional nuclei.

  • 19.
    Andgren, Karin
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Podolyak, Zsolt
    Univ Surrey, Dept Phys.
    Dewald, Alfred
    Univ Cologne, Inst Kernphys.
    Xu, Fu-Rong
    Peking Univ, Sch Phys.
    Algora, Alejandro
    IFIC, Valencia.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics.
    et al.,
    Lifetime measurements of normal deformed states in Lu-165(71)2005In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 71, no 1, p. 121-127Article in journal (Refereed)
    Abstract [en]

    Picosecond lifetimes of medium spin states in Lu-165 were measured for the first time. The reaction used to populate the nucleus of interest was La-139(Si-30,4n)Lu-165 at a beam energy of 135 MeV. The beam was provided by the XTU-tandem accelerator of Laboratori Nazionali di Legnaro, Italy. By using the differential decay curve method, lifetimes of 19 states in four different rotational bands were obtained. Therefrom the B(E2) values and the transitional quadrupole moments were deduced. The obtained Q(t) for the different bands are compared with total Routhian surface (TRS) calculations and particle-rotor-model calculations. The TRS calculations predict different axial symmetric shapes for the bands built on the 9/2(-)[514], 9/2(+)[404], and 1/2(-)[541] configurations, with a gamma softness for the 9/2(-)[514] configuration. This band has also been studied using the particle-rotor model, the results of which, however, are consistent with a triaxial shape with a gamma value of -15(p).

  • 20. Andreyev, A. N.
    et al.
    Ackermann, D.
    Hessberger, F. P.
    Heyde, K.
    Hofmann, S.
    Huyse, M.
    Karlgren, Daniel
    KTH, Superseded Departments, Physics.
    Kojouharov, I.
    Kindler, B.
    Lommel, B.
    Munzenberg, G.
    Page, R. D.
    de Vel, K. V.
    Van Duppen, P.
    Walters, W. B.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Shape-changing particle decays of Bi-185 and structure of the lightest odd-mass Bi isotopes2004In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 69, no 5, p. 054308-Article in journal (Refereed)
    Abstract [en]

    Proton and alpha decay of the proton-rich nuclide Bi-185 has been restudied in more detail in the complete fusion reaction Nb-93(Mo-95, 3n)Bi-185 at the velocity filter SHIP. The observed decay pattern of Bi-185 and of the heavier odd-mass isotopes Bi-187,Bi-189,Bi-191,Bi-193 are interpreted based on potential-energy surface calculations. It is shown that the experimental systematics of the particle decays and of the excited states in these nuclei (where known) can be explained by the prolate-oblate shape co-existence at low excitation energy. The observed state in Bi-185 is proposed to be of prolate nature, which is in contrast with the previously proposed oblate interpretation.

  • 21. Andreyev, A. N.
    et al.
    Antalic, S.
    Ackermann, D.
    Franchoo, S.
    Hessberger, F. P.
    Hofmann, S.
    Huyse, M.
    Kojouharov, I.
    Kindler, B.
    Kuusiniemi, P.
    Lesher, S. R.
    Lommel, B.
    Mann, R.
    Munzenberg, G.
    Nishio, K.
    Page, R. D.
    Ressler, J. J.
    Streicher, B.
    Saro, S.
    Sulignano, B.
    Van Duppen, P.
    Wiseman, D.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    alpha-decay of the new isotope Po-187: Probing prolate structures beyond the neutron mid-shell at N=1042006In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 73, no 4, p. 044324-Article in journal (Refereed)
    Abstract [en]

    The new neutron-deficient isotope Po-187 has been identified in the complete fusion reaction Ti-46+Sm-144 -> Po-187+3n at the velocity filter SHIP. Striking features of the Po-187 alpha decay are the strongly-hindered decay to the spherical ground state and unhindered decay to a surprisingly low-lying deformed excited state at 286 keV in the daughter nucleus Pb-183. Based on the potential energy surface calculations, the Po-187 ground state and the 286 keV excited state in Pb-183 were interpreted as being of prolate origin. The systematic deviation of the alpha-decay properties in the lightest odd-A Po isotopes relative to the smooth behavior in the even-A neighbors is discussed. Improved data for the decay of Bi-187(m,g) were also obtained.

  • 22. Andreyev, A. N.
    et al.
    Antalic, S.
    Huyse, M.
    Van Duppen, P.
    Ackermann, D.
    Bianco, L.
    Cullen, D. M.
    Darby, I. G.
    Franchoo, S.
    Heinz, S.
    Hessberger, F. P.
    Hofmann, S.
    Kojouharov, I.
    Kindler, B.
    Leppanen, A. P.
    Lommel, B.
    Mann, R.
    Muenzenberg, G.
    Pakarinen, J.
    Page, R. D.
    Ressler, J. J.
    Saro, S.
    Streicher, B.
    Sulignano, B.
    Thomson, J.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    alpha decay of the new isotopes Rn-193,Rn-1942006In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 74, no 6, p. 064303-Article in journal (Refereed)
    Abstract [en]

    The new neutron-deficient isotopes Rn-193,Rn-194 have been identified in the complete fusion reaction Cr-52+Sm-144 -> Rn-196(*) at the velocity filter SHIP. The alpha-decay energy and half-life value of Rn-194 were determined to be E-alpha=7700(10) keV and T-1/2=0.78(16) ms, respectively. For Rn-193 the half-life of T-1/2=1.15(27) ms and two alpha lines at E-alpha 1=7685(15) keV, I-alpha 1=74(20)% and E-alpha 2=7875(20) keV, I-alpha 2=26(12)% were found. The decay pattern of Rn-193, which is substantially different from that of the heavier odd-A Rn isotopes, provides first experimental evidence for the long-predicted deformation in the very neutron-deficient Rn nuclei.

  • 23. Andreyev, A. N.
    et al.
    Huyse, M.
    Van de Vel, K.
    Van Duppen, P.
    Dorvaux, O.
    Greenlees, P.
    Helariutta, K.
    Jones, P.
    Julin, R.
    Juutinen, S.
    Kettunen, H.
    Kuusiniemi, P.
    Leino, M.
    Muikku, M.
    Nieminen, P.
    Rahkila, P.
    Uusitalo, J.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Hauschild, K.
    Le Coz, Y.
    In-beam and alpha-decay spectroscopy of Po-191 and evidence for triple shape coexistence at low energy in the daughter nucleus Pb-1872002In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 66, no 1Article in journal (Refereed)
    Abstract [en]

    Prompt gamma rays have been observed for the first time from the neutron-deficient nucleus Po-191 using the recoil-decay tagging technique at the RITU gas-filled separator. In addition improved alpha decay data have been measured for Po-191 and its daughter product Pb-187. The complementary gamma- and alpha-decay data point to the onset of oblate deformation in the light odd-mass Po nuclei by approaching the neutron midshell at N=104. The pattern of the favored and unfavored states observed on top of the 13/2(+) isomer in Po-191 indicates a change from the weak-coupling towards the strong-coupling scheme in Po-191m. In the daughter nucleus Pb-187, the 13/2(+) and 3/2(-) isomeric states become degenerate within the experimental accuracy. Evidence for triple shape coexistence at low energy has been found in the high-spin isomer in Pb-187. The results are supported by potential-energy surface calculations and by particle-plus-rotor calculations.

  • 24. Ashley, S. F.
    et al.
    Regan, P. H.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    McCutchan, E. A.
    Zamfir, N. V.
    Amon, L.
    Cakirli, R. B.
    Casten, R. F.
    Clark, R. M.
    Gelletly, W.
    Gürdal, G.
    Keyes, K. L.
    Meyer, D. A.
    Erduran, M. N.
    Papenberg, A.
    Pietralla, N.
    Plettner, C.
    Rainovski, G.
    Ribas, R. V.
    Thomas, N. J.
    Vinson, J.
    Warner, D. D.
    Werner, V.
    Williams, E.
    Liu, H. L.
    Xu, F. R.
    Intrinsic state lifetimes in Pd-103 and Cd-106,Cd-1072007In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 76, no 6, p. 064302-Article in journal (Refereed)
    Abstract [en]

    The mean-lifetimes, tau, of various medium-spin excited states in Pd-103 and Cd-106,Cd-107 have been deduced using the Recoil Distance Doppler Shift technique and the Differential Decay Curve Method. In Cd-106, the mean-lifetimes of the I-pi=12(+) state at E-x=5418 keV and the I-pi=11(-) state at E-x=4324 keV have been deduced as 11.4(17)ps and 8.2(7)ps, respectively. The associated beta(2) deformation within the axially-symmetric deformed rotor model for these states are 0.14(1) and 0.14(1), respectively. The beta(2) deformation of 0.14(1) for the I-pi=12(+) state in Cd-106 compares with a predicted beta(2) value from total Routhian surface (TRS) calculations of 0.17. In addition, the mean-lifetimes of the yrast I-pi = 15(-)/2 states in Pd-103 (at E-x=1262 keV) and Cd-107 (at E-x=1360 keV) have been deduced to be 31.2(44)ps and 31.4(17)ps, respectively, corresponding to beta(2) values of 0.16(1) and 0.12(1) assuming axial symmetry. Agreement with TRS calculations are good for Pd-103 but deviate for that predicted for Cd-107.

  • 25. Asztalos, S J
    et al.
    Lee, I Y
    Vetter, K
    Cederwall, B
    Clark, R M
    Deleplanque, M A
    Diamond, R M
    Fallon, P
    Jing, K
    Phair, L
    Macchiavelli, A O
    Rasmussen, J O
    Stephens, F S
    Wozniak, G J
    Becker, J A
    Bernstein, L A
    McNabb, D P
    Hua, P F
    Sarantites, D G
    Saladin, J X
    Yu, C H
    Cizewski, J A
    Donangelo, R
    Spin yields of neutron-rich nuclei from deep inelastic reactions1999In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 60, no 4, article id 044307Article in journal (Refereed)
    Abstract [en]

    The potential for using deep inelastic reactions to populate high-spin states in neutron-rich nuclei is studied in a series of experiments using GAMMASPHERE for gamma-ray detection and a silicon strip detector for measuring the angles of projectilelike and targetlike fragments. In three experiments 61 new transitions up to a maximum spin of 22 (h) over bar in 12 neutron-rich rare-earth nuclei were found. We observe that gamma-ray yields as a function of spin are flatter for all neutron transfer products than for inelastic excitation of either the projectile or target nucleus. Calculations are presented which indicate that this difference cannot be accounted for by quasielastic processes, but more likely are the result of larger energy loss processes, such as deep inelastic reactions. [S0556-2813(99)06009-4].

  • 26. Asztalos, S. J.
    et al.
    Lee, I. Y.
    Vetter, K.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    Clark, R. M.
    Deleplanque, M. A.
    Diamond, R. M.
    Fallon, P.
    Jing, K.
    Phair, L.
    Macchiavelli, A. O.
    Stephens, F. S.
    Wozniak, G. J.
    Bernstein, L. A.
    McNabb, D. P.
    Hua, P. F.
    Sarantites, D. G.
    Saladin, J. X.
    Yu, C. H.
    Cizewski, J. A.
    Isotopic yields of neutron-rich nuclei from deep-inelastic reactions2000In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 6101, no 1Article in journal (Refereed)
    Abstract [en]

    We follow up on our earlier work involving a light projectile (Ca-48) to populate high spin states in neutron-rich nuclei with results from experiments involving a heavier projectile (Sm-154) fur the purposes of studying isotopic yields. These yields, which in some cases were mensurable down to a level of 0.1 of the total reaction cross section, are presented from three separate reactions. A trend in the isotopic yields towards N/Z equilibration is observed in one experiment having a large disparity in N/Z ratios between the projectile and target. In the two other reactions, where the N/Z driving force is less pronounced, the yields are instead clustered around the projectile and target nuclei. We present correlated projectilelike and targetlike fragment isotopic yields derived from gamma-gamma coincidences, a technique that enables one to partition the yield of an isotope according to the amount of neutron evaporation. Using this method we find that for the zero-neutron evaporation channel transfer occurs predominantly into the light fragment, consistent with the nature of the deep-inelastic mechanism. We further find that multiple-neutron evaporation contributes substantially to the yields of the isotopes.

  • 27. Baldsiefen, G
    et al.
    Stoyer, M A
    Cizewski, J A
    Mcnabb, D P
    Younes, W
    Becker, J A
    Bernstein, L A
    Brinkman, M J
    Farris, L P
    Henry, E A
    Hughes, J R
    Kuhnert, A
    Wang, T F
    Cederwall, Bo
    Clark, R M
    Deleplanque, M A
    Diamond, R M
    Fallon, P
    Lee, I Y
    Macchiavelli, A O
    Oliveira, J
    Stephens, F S
    Burde, J
    Vo, D T
    Frauendorf, S
    Shears bands in Pb-1931996In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 54, no 3, p. 1106-1116Article in journal (Refereed)
    Abstract [en]

    Four bands of enhanced dipole transitions, with weak crossovers, have been observed in Pb-195. Three of these bands are connected to the spherical levels. in addition, the spherical level scheme has been extended. The nuclear spectroscopy was done with the early implementation of GAMMASPHERE and HERA arrays of Get detectors. The nucleus Pb-193 was populated in the Yb-174(Mg-24,5n) reaction at beam energies of 129, 131, and 134 MeV. The experimental results are compared to tilted-axis cranking calculations. The systematical behavior of the dipole bands in the heavier odd-A Pb isotopes, Pb-195,Pb-197,Pb-199,Pb-201, is also discussed.

  • 28.
    Ban, Shufang
    et al.
    School of Physics, Peking University.
    Li, J
    College of Physics and Technology, Wuhan University.
    Zhang, SQ
    School of Physics, Peking University.
    Jia, HY
    School of Physics, Peking University; College of Science, Southwest Jiaotong University.
    Sang, JP
    ollege of Physics and Technology, Wuhan University.
    Meng, J
    School of Physics, Peking University; Institute of Theoretical Physics, Chinese Academy of Science; Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator.
    Density dependencies of interaction strengths and their influences on nuclear matter and neutron stars in relativistic mean field theory2004In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 69, no 4Article in journal (Refereed)
    Abstract [en]

    The density dependencies of various effective interaction strengths in the relativistic mean field are studied and carefully compared for nuclear matter and neutron stars. The influences of different density dependencies are presented and discussed on mean field potentials, saturation properties for nuclear matter, equations of state, maximum masses, and corresponding radii for neutron stars. Though the interaction strengths and the potentials given by various interactions are quite different in nuclear matter, the differences of saturation properties are subtle, except for NL2 and TM2, which are mainly used for light nuclei, while the properties by various interactions for pure neutron matter are quite different. To get an equation of state for neutron matter without any ambiguity, it is necessary to constrain the effective interactions either by microscopic many-body calculations for the neutron matter data or the data of nuclei with extreme isospin. For neutron stars, the interaction with large interaction strengths give strong potentials and large Oppenheimer-Volkoff (OV) mass limits. The density-dependent interactions DD-ME1 and TW-99 favor a large neutron population due to their weak rho-meson field at high densities. The OV mass limits calculated from different equations of state are 2.02-2.81M, and the corresponding radii are 10.78-13.27 km. After the inclusion of the hyperons, the corresponding values become 1.52-2.06M and 10.24-11.38 km.

  • 29. BERNSTEIN, LA
    et al.
    CIZEWSKI, JA
    JIN, HQ
    YOUNES, W
    HENRY, RG
    FARRIS, LP
    CHAROS, A
    CARPENTER, MP
    JANSSENS, RVF
    KHOO, TL
    LAURITSEN, T
    BEARDEN, IG
    YE, D
    BECKER, JA
    HENRY, EA
    BRINKMAN, MJ
    HUGHES, JR
    KUHNERT, A
    WANG, TF
    STOYER, MA
    DIAMOND, RM
    STEPHENS, FS
    DELEPLANQUE, MA
    MACCHIAVELLI, AO
    LEE, IY
    Cederwall, Bo
    OLIVEIRA, JRB
    BURDE, J
    FALLON, P
    DUYAR, C
    DRAPER, JE
    RUBEL, E
    VO, DT
    ONSET OF COLLECTIVITY IN NEUTRON-DEFICIENT PO-196,PO-1981995In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 52, no 2, p. 621-627Article in journal (Refereed)
    Abstract [en]

    We have studied via in-beam gamma-ray spectroscopy Po-196 and Po-198, which are the first neutron-deficient Po isotopes to exhibit a collective low-lying structure. The ratios of yrast state energies and the E2 branching ratios of transitions from non-yrast to yrast states are indicative of a low-lying vibrational structure. The onset of collective motion in these isotopes can be attributed to the opening of the neutron i(13/2) orbital at N approximate to 112 and the resulting large overlap between the two valence protons in the h(9/2) orbital and the valence neutrons in the i(13/2) orbital.

  • 30. BERNSTEIN, LA
    et al.
    HUGHES, JR
    BECKER, JA
    FARRIS, LP
    HENRY, EA
    ASZTALOS, SJ
    Cederwall, Bo
    CLARK, RM
    DELEPLANQUE, MA
    DIAMOND, RM
    FALLON, P
    LEE, IY
    MACCHIAVELLI, AO
    STEPHENS, FS
    CIZEWSKI, JA
    YOUNES, W
    SUPERDEFORMATION IN ER-1541995In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 52, no 3, p. R1171-R1174Article in journal (Refereed)
    Abstract [en]

    A superdeformed (SD) band consisting of 13 gamma-ray transitions has been observed in Er-154, an isotone of Dy-152(66). The experiment was performed using the Sn-118(Ar-40,4n) reaction at E(Ar-40)=185 MeV and the early implementation of GAMMASPHERE. This is an observation of a SD band in the A approximate to 150 region with a proton number greater than 66. The J((2)) moment of inertia of the band is constant above ($) over bar h omega=0.45 MeV and shows a sharp rise below this value suggesting a paired band crossing. These results suggest that total Routhian surface calculations fail to accurately predict the deformation of the band.

  • 31. Bhagwat, A.
    et al.
    Vinas, X.
    Centelles, M.
    Schuck, P.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Microscopic-macroscopic approach for binding energies with the Wigner-Kirkwood method. II. Deformed nuclei2012In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 86, no 4, p. 044316-Article in journal (Refereed)
    Abstract [en]

    The binding energies of deformed even-even nuclei have been analyzed within the framework of a recently proposed microscopic-macroscopic model. We have used the semiclassical Wigner-Kirkwood (h) over bar expansion up to fourth order, instead of the usual Strutinsky averaging scheme, to compute the shell corrections in a deformed Woods-Saxon potential including the spin-orbit contribution. For a large set of 561 even-even nuclei with Z >= 8 and N >= 8, we find an rms deviation from the experiment of 610 keV in binding energies, comparable to the one found for the same set of nuclei using the finite range droplet model of Moller and Nix (656 keV). As applications of our model, we explore its predictive power near the proton and neutron drip lines as well as in the superheavy mass region. Next, we systematically explore the fourth-order Wigner-Kirkwood corrections to the smooth part of the energy. It is found that the ratio of the fourth-order to the second-order corrections behaves in a very regular manner as a function of the asymmetry parameter I = (N - Z)/A. This allows us to absorb the fourth-order corrections into the second-order contributions to the binding energy, which enables us to simplify and speed up the calculation of deformed nuclei.

  • 32.
    Bhagwat, Ameeya
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Simple nuclear mass formula2014In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 90, no 6, p. 064306-Article in journal (Refereed)
    Abstract [en]

    A simple formula for ground state nuclear masses based on the microscopic-macroscopic approach is proposed. Considering a set of 2353 nuclei with Z >= 8 and N >= 8, the formula yields an rms deviation of just 266 keV. A few applications, including the loosely bound proton rich nuclei, superheavy nuclei, and cluster emitters, are presented and discussed, establishing the reliability of the proposed formula. The present investigation has a major advantage: it allows one to reliably parametrize the fluctuating part of the ground state energy. This result is very interesting and important, since the fluctuating part of the energy is related directly to the trace formula, which in turn encodes the interaction itself.

  • 33.
    Bhagwat, Ameeya
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Gambhir, Y. K.
    Microscopic description of measured reaction cross sections at low projectile energies2006In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 73, no 2, p. 024604-Article in journal (Refereed)
    Abstract [en]

    Systematic and consistent microscopic description of measured reaction cross sections at low projectile en-ergies is presented. Finite-range Glauber model (GM-F) along with the Coulomb modification is used. The required inputs, namely the neutron and proton density distributions of the relevant projectiles and the targets, are calculated in the relativistic mean field framework. The GM-F reproduces the experiment well. At high projectile energies both the GM-F and the zero-range Glauber model in the optical limit (GM-Z) yield almost identical results; however, the GM-F in general is superior at low projectile energies, as expected.

  • 34.
    Bhagwat, Ameeya
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Gambhir, Y. K.
    Microscopic description of recently measured reaction cross sections of neutron-rich nuclei in the vicinity of the N=20 and N=28 closed shells2008In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 77, no 2, p. 027602-Article in journal (Refereed)
    Abstract [en]

    The reaction cross sections for neutron-rich nuclei with 7 <= Z <= 18 on a Si-28 target at intermediate energies (30-65A MeV) are calculated and are compared with the corresponding recently reported new measurements. A finite-range Glauber model along with a Coulomb modification is used. The required nucleon density distributions of the relevant projectiles and the targets are obtained in the relativistic mean field framework. The calculations reproduce the experiment well. A simple phenomenological modification of the zero-range Glauber model is proposed to incorporate the finite-range effects. This one-parameter expression is found to reproduce the experimental reaction cross sections quite well.

  • 35.
    Bhagwat, Ameeya
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Gambhir, Y. K.
    Recently measured reaction cross sections with low energy fp-shell nuclei as projectiles: Microscopic description2006In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 73, no 5, p. 054601-Article in journal (Refereed)
    Abstract [en]

    The finite range Glauber model along with the Coulomb modification is used to analyze recently measured reaction cross sections with neutron-deficient Ga, Ge, As, Se, and Br isotopes as low-energy projectiles incident on Si-28 target. The required input, namely the neutron and proton density distributions of the relevant projectiles and the target, are calculated in the relativistic mean-field framework. Though the calculations qualitatively agree with the experiment, on the average, slightly overestimate the cross sections. A phenomenological expression with a single parameter is proposed that consistently improves the agreement with the experiment.

  • 36.
    Bhagwat, Ameeya
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. UM-DAE Centre for Excellence in Basic Sciences, Mumbai, India.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Consistent description of the cluster-decay phenomenon in transactinide nuclei2015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 92, no 4Article in journal (Refereed)
    Abstract [en]

    Systematic investigation of the known even-even transactinide cluster emitters has been carried out by considering the cluster as a point particle and using the exact quantum mechanical treatment of the decay process. It is shown that the cluster decay phenomenon can be described reasonably well using a simple Woods-Saxon mean field. Sensitivity of the half-lives on various aspects of the mean field has been investigated in detail.

  • 37.
    Bhagwat, Ameeya
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Vinas, X.
    Centelles, M.
    Schuck, P.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Microscopic-macroscopic approach for binding energies with the Wigner-Kirkwood method2010In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 81, no 4, p. 044321-Article in journal (Refereed)
    Abstract [en]

    The semiclassical Wigner-Kirkwood h expansion method is used to calculate shell corrections for spherical and deformed nuclei. The expansion is carried out up to fourth order in h. A systematic study of Wigner-Kirkwood averaged energies is presented as a function of the deformation degrees of freedom. The shell corrections, along with the pairing energies obtained by using the Lipkin-Nogami scheme, are used in the microscopic-macroscopic approach to calculate binding energies. The macroscopic part is obtained from a liquid drop formula with six adjustable parameters. Considering a set of 367 spherical nuclei, the liquid drop parameters are adjusted to reproduce the experimental binding energies, which yields a root mean square (rms) deviation of 630 keV. It is shown that the proposed approach is indeed promising for the prediction of nuclear masses.

  • 38. Blazhev, A.
    et al.
    Gorska, M.
    Grawe, H.
    Nyberg, J.
    Palacz, M.
    Caurier, E.
    Cederwall, Bo
    KTH, Superseded Departments, Physics.
    et al,
    Observation of a core-excited E4 isomer in Cd-982004In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 69, no 6Article in journal (Refereed)
    Abstract [en]

    A core-excited I-pi=(12(+)) spin-gap isomer was identified in Cd-98 in an experiment at EUROBALL IV. It was found to feed the known I-pi=(8(+)) seniority isomer by an E4 transition. Half-lives of T-1/2=0.23 ((+4)(-3)) mus and 0.17 ((+6)(-4)) mus were measured for the two states at E-x=6635 keV and 2428 keV, respectively. From the excitation energy of the core-excited isomer a Sn-100 shell gap of 6.46(15) MeV is inferred. The measured E4 and E2 strengths, Sn-100 core excitations and the origin of empirical polarization charges are discussed in the framework of large-scale shell model calculations. An E2 polarization charge for protons of deltae(pi)

  • 39.
    Blideanu, V.
    et al.
    LPC, ENSICAEN, Université de Caen, CNRS∕IN2P3, Caen, France.
    Lecolley, F.-R.
    LPC, ENSICAEN, Université de Caen, CNRS∕IN2P3, Caen, France.
    Lecolley, J.-F.
    LPC, ENSICAEN, Université de Caen, CNRS∕IN2P3, Caen, France.
    Lefort, T.
    LPC, ENSICAEN, Université de Caen, CNRS∕IN2P3, Caen, France.
    Marie, N.
    LPC, ENSICAEN, Université de Caen, CNRS∕IN2P3, Caen, France.
    Ataç, Ayşe
    Department of Neutron Research, Uppsala University, Sweden.
    Ban, G.
    LPC, ENSICAEN, Université de Caen, CNRS∕IN2P3, Caen, France.
    Bergenwall, B.
    Department of Neutron Research, Uppsala University, Sweden.
    Blomgren, J.
    Department of Neutron Research, Uppsala University, Sweden.
    Dangtip, S.
    Department of Neutron Research, Uppsala University, Sweden.
    Elmgren, K.
    Eudes, Ph.
    Foucher, Y.
    Guertin, A.
    Haddad, F.
    Hildebrand, A.
    Johansson, C.
    Jonsson, O.
    Kerveno, M.
    Kirchner, T.
    Klug, J.
    Le Brun, Ch.
    Lebrun, C.
    Louvel, M.
    Nadel-Turonski, P.
    Nilsson, L.
    Olsson, N.
    Pomp, S.
    Prokofiev, A. V.
    Renberg, P.-U.
    Riviere, G.
    Slypen, I.
    Stuttge, L.
    Tippawan, U.
    Österlund, M.
    Nucleon-induced reactions at intermediate energies: New data at 96 MeV and theoretical status2004In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 70, no 1, p. 014607-Article in journal (Refereed)
    Abstract [en]

    Double-differential cross sections for light charged particle. production (up to A=4) were measured in 96 MeV neutron-induced reactions, at the TSL Laboratory Cyclotron in Uppsala (Sweden). Measurements for three targets, Fe, Pb, and U, were performed using two independent devices, SCANDAL and MEDLEY. The data were recorded with low-energy thresholds and for a wide angular range (20degrees-160degrees). The normalization procedure used to extract the cross sections is based on the up elastic scattering reaction that we measured and for, which we present experimental results. A good control of the systematic uncertainties affecting the results is achieved. Calculations using the exciton model are reported, Two different theoretical approaches proposed to improve its predictive power regarding the complex particle emission are tested. The capabilities of each approach is illustrated by comparison with the 96 MeV data that we measured, and with, other experimental results available in the literature.

  • 40.
    Boutachkov, P.
    et al.
    GSI, Planckstraße 1, 64291 Darmstadt, Germany.
    Gorska, M.
    GSI, Planckstraße 1, 64291 Darmstadt, Germany.
    Grawe, H.
    Blazhev, A.
    Braun, N.
    Brock, T.S.
    Liu, Z.
    Nara Singh, B.S.
    Wadsworth, R.
    Pietri, S.
    Domingo-Pardo, C.
    Kojouharov, I.
    C´aceres, L.
    Engert, T.
    Farinon, F.
    Gerl, J.
    Goel, N.
    Grebosz, J.
    Hoischen, R.
    Kurz, N.
    Nociforo, C.
    Prochazka, A.
    Schaffner, H.
    Steer, S. J.
    Weick, H.
    Wollersheim, H-J.
    Faestermann, T.
    Padolyak, Zs.
    Rudolph, D.
    Ataç, Ayşe
    Department of Physics, Ankara University, 06100 Tandogan Ankara, Turkey.
    Bettermann, L.
    Eppinger, K.
    Finke, F.
    Geibel, K.
    Gottardo, A.
    Hinke, C.
    Ilie, G.
    Iwasaki, H.
    Jolie, J.
    Krucken, R.
    Merchan, E.
    Nyberg, Johan
    Univ. of Uppsala, P. O. Box 535, S-75121 Uppsala, Sweden.
    Pf¨utzner, M.
    Regan, P. H.
    Reiter, P.
    Rinta-Antila, S.
    Scholl, C.
    Soderstrom, P.-A.
    Warr, N.
    Woods, P. J.
    Nowacki, F.
    Sieja, K.
    High-spin isomers in 96Ag: excitations across the Z=38 and Z=50, N=50 closed shells2011In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 84, no 4Article in journal (Refereed)
    Abstract [en]

    Excited states in (96)Ag were populated in fragmentation of an 850-MeV/u (124)Xe beam on a 4-g/cm(2) Be target. Three new high-spin isomers were identified and the structure of the populated states was investigated. The level scheme of (96)Ag was established, and a spin parity of (13(-)), (15(+)), and (19(+)) was assigned to the new isomeric states. Shell-model calculations were performed in various model spaces, including pi nu(p(1/2), g(9/2), f(5/2), p(3/2)) and the large-scale shell-model space pi nu(gds), to account for the observed parity changing M2 and E3 transitions from the (13(-)) isomer and the E2 and E4 transitions from the (19(+)) core-excited isomer, respectively. The calculated level schemes and reduced transition strengths are found to be in very good agreement with the experiment.

  • 41. Brinkman, M J
    et al.
    Becker, J A
    Lee, I Y
    Farris, L P
    Henry, E A
    Hoff, R W
    Hughes, J R
    Stoyer, M A
    Bernstein, L A
    Cizewski, J A
    Jin, H Q
    Younes, W
    Cederwall, Bo
    Deleplanque, M A
    Diamond, R M
    Fallon, P
    Macchiavelli, A O
    Stephens, F S
    Kelly, W H
    Vo, D T
    Draper, J E
    Duyar, C
    Rubel, E
    Decay from a superdeformed band in Pb-1941996In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 53, no 4, p. R1461-R1464Article in journal (Refereed)
    Abstract [en]

    Three experiments using the (174) Yb(Mg-25,5n)Pb-194 reaction have been undertaken at the Early Implementation of Gammasphere to study the decay of known superdeformed states in Pb-194. A single discrete transition with an energy of 2.746(2) MeV carrying 6(2)% of the full superdeformed band intensity has been identified. A discussion of our results and the assignment of the 2.746-MeV transition as a discrete gamma ray directly connecting the superdeformed 8(+) and low-lying 6(+) levels will be presented.

  • 42. Brock, T.S.
    et al.
    Ataç, Ayşe
    Department of Physics, Ankara University, 06100 Tandogan, Ankara, Turkey.
    Woods, P.J
    et, al.
    Observation of a new high-spin isomer in 94Pd.2010In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 82, no 6Article in journal (Refereed)
    Abstract [en]

    A second gamma-decaying high-spin isomeric state, with a half-life of 197(22) ns, has been identified in the N = Z + 2 nuclide (94)Pd as part of a stopped-beam Rare Isotope Spectroscopic INvestigation at GSI (RISING) experiment. Weisskopf estimates were used to establish a tentative spin/parity of 19(-), corresponding to the maximum possible spin of a negative parity state in the restricted (p(1/2), g(9/2)) model space of empirical shell model calculations. The reproduction of the E3 decay properties of the isomer required an extension of the model space to include the f (5/2) and p(3/2) orbitals using the CD-Bonn potential. This is the first time that such an extension has been required for a high-spin isomer in the vicinity of (100)Sn and reveals the importance of such orbits for understanding the decay properties of high-spin isomers in this region. However, despite the need for the extended model space for the E3 decay, the dominant configuration for the 19(-) state remains (p p(1/2)(-1)g(9/2)(-3))(11)circle times(nu g(9/2)(-2))(8). The half-life of the known, 14(+), isomer was remeasured and yielded a value of 499(13) ns.

  • 43. Bruce, A. M.
    et al.
    Simpson, J.
    Warner, D. D.
    Baktash, C.
    Barton, C. J.
    Bentley, M. A.
    Brinkman, M. J.
    Cunningham, R. A.
    Dragulescu, E.
    Frankland, L.
    Ginter, T. N.
    Gross, C. Y.
    Lemmon, R. C.
    MacDonald, B.
    O'Leary, C. D.
    Vincent, S. M.
    Wyss, Ramon
    KTH, Superseded Departments, Physics.
    Yu, C. H.
    Zamfir, N. V.
    Two-neutron alignment and shape changes in As-692000In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 6202, no 2Article in journal (Refereed)
    Abstract [en]

    The nucleus As-69 was Studied using the Ca-40(S-32,3p)As-69 reaction at a beam energy of 105 MeV. An extension of the band built on the g(9/2) orbital was observed to exhibit a band crossing at a rotational frequency of 0.511 MeV with an associated alignment of 7 (h) over bar. This alignment is interpreted as being due to a pair of g(9/2) neutrons. Total Routhian surface calculations have been carried out which confirm that the shape of this nucleus changes from oblate at low spin to a triaxial prolate shape at intermediate spin.

  • 44.
    Bäck, Torbjörn
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ghazi Moradi, Farnaz
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wadsworth, R.
    Transition probabilities near Sn-100 and the stability of the N, Z=50 shell closure2013In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 87, no 3, p. 031306-Article in journal (Refereed)
    Abstract [en]

    Recent B(E2; 0(g.s.)(+) -> 2(1)(+)) measurements in light tin isotopes have revealed surprisingly large values relative to standard shell model predictions, generating an unexpected asymmetry in the B(E2) values with respect to the neutron midshell. This effect has triggered various speculations as to its origin, such as a possible weakening of the N, Z = 50 shell closure. Here we present new shell model calculations to investigate the origin of the observed asymmetric character of the B(E2) values in the tin isotopes. By including the effects of the neutron g(9/2) orbital below the N = 50 shell gap it is shown that Pauli blocking effects may play an important role near the N = 50 shell closure. A new set of single-particle energies and monopole interactions, fitted to the experimental data in the region, together with the isospin-dependent effective charge suggested by Bohr and Mottelson is shown to reproduce the experimental transition rate values in the Sn isotopic chain.

  • 45.
    Bäck, Torbjörn
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Ghazi Moradi, Farnaz
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Johnson, Arne
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liotta, Roberto
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Al-Azri, H.
    Bloor, D.
    Brock, T.
    Wadsworth, R.
    Grahn, T.
    Greenlees, P. T.
    Hauschild, K.
    Herzan, A.
    Jacobsson, U.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Leino, M.
    Lopez-Martens, A.
    Nieminen, P.
    Peura, P.
    Rahkila, P.
    Rinta-Antila, S.
    Ruotsalainen, P.
    Sandzelius, M.
    Saren, J.
    Scholey, C.
    Sorri, J.
    Uusitalo, J.
    Go, S.
    Ideguchi, E.
    Cullen, D. M.
    Procter, M. G.
    Braunroth, T.
    Dewald, A.
    Fransen, C.
    Hackstein, M.
    Litzinger, J.
    Rother, W.
    Lifetime measurement of the first excited 2(+) state in (108)Te2011In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 84, no 4, p. 041306-Article in journal (Refereed)
    Abstract [en]

    The lifetime of the first excited 2(+) state in the neutron deficient nuclide (108)Te has been measured for the first time, using a combined recoil decay tagging and recoil distance Doppler shift technique. The deduced reduced transition probability is B(E2;0(g.s.)(+) -> 2(+)) = 0.39(-0.04)(+0.05)e(2)b(2). Compared to previous experimental data on neutron deficient tellurium isotopes, the new data point constitutes a large step (six neutrons) toward the N = 50 shell closure. In contrast to what has earlier been reported for the light tin isotopes, our result for tellurium does not show any enhanced transition probability with respect to the theoretical predictions and the tellurium systematics including the new data is successfully reproduced by state-of-the-art shell model calculations.

  • 46. Caceres, L.
    et al.
    Gorska, M.
    Jungclaus, A.
    Pfutzner, M.
    Grawe, H.
    Nowacki, F.
    Sieja, K.
    Pietri, S.
    Rudolph, D.
    Podolyak, Zs.
    Regan, P. H.
    Werner-Malento, E.
    Detistov, P.
    Lalkovski, S.
    Modamio, V.
    Walker, J.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics.
    Bednarczyk, P.
    Benlliure, J.
    Benzoni, G.
    Bruce, A. M.
    Casarejos, E.
    Cederwall, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Crespi, F. C. L.
    Doornenbal, P.
    Geissel, H.
    Gerl, J.
    Grebosz, J.
    Hadinia, Bahrak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Hellstrom, M.
    Hoischen, R.
    Ilie, G.
    Khaplanov, Anton
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Kmiecik, M.
    Kojouharov, I.
    Kumar, R.
    Kurz, N.
    Maj, A.
    Mandal, S.
    Montes, F.
    Martinez-Pinedo, G.
    Myalski, S.
    Prokopowicz, W.
    Schaffner, H.
    Simpson, G. S.
    Steer, S. J.
    Tashenov, S.
    Wieland, O.
    Wollersheim, H. J.
    Spherical proton-neutron structure of isomeric states in Cd-1282009In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 79, no 1, p. 011301-Article in journal (Refereed)
    Abstract [en]

    The gamma-ray decay of isomeric states in the even-even nucleus Cd-128 has been observed. The nucleus of interest was produced both by the fragmentation of Xe-136 and the fission of U-238 primary beams. The level scheme was unambiguously constructed based on.. coincidence relations in conjunction with detailed lifetime analysis employed for the first time on this nucleus. Large-scale shell-model calculations, without consideration of excitations across the N = 82 shell closure, were performed and provide a consistent description of the experimental level scheme. The structure of the isomeric states and their decays exhibit coexistence of proton, neutron, and strongly mixed configurations due to p. interaction in overlapping orbitals for both proton and neutron holes.

  • 47. Caceres, L.
    et al.
    Lepailleur, A.
    Sorlin, O.
    Stanoiu, M.
    Sohler, D.
    Dombradi, Zs.
    Bogner, S. K.
    Brown, B. A.
    Hergert, H.
    Holt, J. D.
    Schwenk, A.
    Azaiez, F.
    Bastin, B.
    Borcea, C.
    Borcea, R.
    Bourgeois, C.
    Elekes, Z.
    Fueloep, Zs.
    Grevy, S.
    Gaudefroy, L.
    Grinyer, G. F.
    Guillemaud-Mueller, D.
    Ibrahim, F.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine.
    Krasznahorkay, A.
    Lewitowicz, M.
    Lukyanov, S. M.
    Mrazek, J.
    Negoita, F.
    de Oliveira, F.
    Penionzhkevich, Yu. -E.
    Podolyak, Zs.
    Porquet, M. G.
    Rotaru, F.
    Roussel-Chomaz, P.
    Saint-Laurent, M. G.
    Savajols, H.
    Sletten, G.
    Thomas, J. C.
    Timar, J.
    Timis, C.
    Vajta, Zs.
    Nuclear structure studies of F-242015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 92, no 1, article id 014327Article in journal (Refereed)
    Abstract [en]

    The structure of the F-24 nucleus has been studied at GANIL using the beta decay of O-24 and the in-beam.-ray spectroscopy from the fragmentation of Na-27,Na-28, Ne-25,Ne-26, and Mg-29,Mg-30 nuclei. Combining these complementary experimental techniques, the level scheme of F-24 has been constructed up to 3.6 MeV by means of particle-gamma and particle-gamma gamma coincidence relations. Experimental results are compared to shell-model calculations using the standard USDA and USDB interactions as well as ab initio valence-space Hamiltonians calculated from the in-medium similarity renormalization group based on chiral two- and three-nucleon forces. Both methods reproduce the measured level spacings well, and this close agreement allows unidentified spins and parities to be consistently assigned.

  • 48. CARPENTER, MP
    et al.
    JANSSENS, RVF
    Cederwall, Bo
    CROWELL, B
    AHMAD, I
    BECKER, JA
    BRINKMAN, MJ
    DELEPLANQUE, MA
    DIAMOND, RM
    FALLON, P
    FARRIS, LP
    GARG, U
    GASSMANN, D
    HENRY, EA
    HENRY, RG
    HUGHES, JR
    KHOO, TL
    LAURITSEN, T
    LEE, IY
    MACHIAVELLI, AO
    MOORE, EF
    NISIUS, D
    STEPHENS, FS
    IDENTIFICATION OF THE UNFAVORED N=7 SUPERDEFORMED BAND IN HG-1911995In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 51, no 5, p. 2400-2405Article in journal (Refereed)
  • 49. Carroll, R. J.
    et al.
    Andgren, Karin
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Cederwal, Bo
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Doncel, Maria
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Hadinia, Baharak
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. Department of Physics, University of Guelph, Guelph, ON, Canada.
    Jacobsson, Ulrika
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics. University of Jyväskylä, Department of Physics, Jyväskylä, Finland.
    Sandzelius, Mikael
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Taylor, M. J.
    Thornthwaite, A.
    et al.,
    Excited states in the proton-unbound nuclide Ta-1582016In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 93, no 3, article id 034307Article in journal (Refereed)
    Abstract [en]

    Excited states in the neutron-deficient odd-odd proton-unbound nuclide Ta-158 have been investigated in two separate experiments. In the first experiment, Ir-166 nuclei were produced in the reactions of 380 MeV Kr-78 ions with an isotopically enriched Mo-92 target. The alpha-decay chain of the 9(+) state in Ir-166 was analyzed. Fine structure in the a decay of the 9(+) state in Re-162 established a 66 keV difference in excitation energy between the lowest-lying 9(+) and 10(+) states in Ta-158. Higher-lying states in Ta-158 were populated in the reactions of 255 MeV Ni-58 ions with an isotopically enriched Pd-102 target. Gamma-ray decay paths that populate, depopulate, and bypass a 19(-) isomeric state have been identified. The general features of the deduced level scheme are discussed and the prospects for observing proton emission branches from excited states are considered.

  • 50. Cederwall, Bo
    et al.
    DELEPLANQUE, MA
    AZAIEZ, F
    DIAMOND, RM
    FALLON, P
    KORTEN, W
    LEE, IY
    MACCHIAVELLI, AO
    OLIVEIRA, JRB
    STEPHENS, FS
    KELLY, WH
    VO, DT
    BECKER, JA
    BRINKMAN, MJ
    HENRY, EA
    HUGHES, JR
    KUHNERT, A
    STOYER, MA
    WANG, TF
    DRAPER, JE
    DUYAR, C
    RUBEL, E
    DEBOER, J
    NEW OBLATE BAND IN HG-196 WITH QUENCHED M1 STRENGTH1993In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 47, no 6, p. R2443-R2446Article in journal (Refereed)
    Abstract [en]

    High-spin states in the nucleUs Hg-196 were populated in the reaction (Os(Be,5n))-Os-192 at a beam energy of 65 MeV. A regular rotational-like DELTAI = 1 band has been observed up to an excitation energy of E* almost-equal-to 8.7 MeV and spin I almost-equal-to 30hBAR. This is the second observation of a band of this character in a mercury isotope. The experimental results are compared with mean field calculations and semiclassical estimates based on the Donau-Frauendorf formalism. The mercury bands show significantly lower B(M1)/B(E2) branching ratios as compared with similar bands in light lead nuclei. This difference may be more readily explained by a difference in single-particle structure rather than by large differences in deformation between the lead and mercury configurations.

12345 1 - 50 of 210
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