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Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 251.
    Hoppe, Jens
    KTH, Skolan för teknikvetenskap (SCI), Matematik (Inst.), Matematik (Avd.).
    Reformulating M-brane equations2008Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 663, nr 4, s. 351-352Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A Lorentz invariant formulation of Born-Infeld M-brane equations that are not diffeomorphism invariant is presented, and their relation to the standard "extremal-volume" equations clarified.

  • 252.
    Hossenfelder, Sabine
    KTH, Centra, Nordic Institute for Theoretical Physics NORDITA. Stockholm University, Sweden.
    A relativistic acoustic metric for planar black holes2016Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 752, s. 13-17Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate here that the metric of a planar black hole in asymptotic anti-de Sitter space can, on a slice of dimension 3. +. 1, be reproduced as a relativistic acoustic metric. This completes an earlier calculation in which the non-relativistic limit was used, and also serves to obtain a concrete form of the Lagrangian.

  • 253.
    Ideguchi, Eiji
    et al.
    KTH, Tidigare Institutioner, Fysik.
    Cederwall, Bo
    KTH, Tidigare Institutioner, Fysik.
    Wyss, Ramon
    KTH, Tidigare Institutioner, Fysik.
    Bäck, Torbjörn
    KTH, Tidigare Institutioner, Fysik.
    Lagergren, Karin
    KTH, Tidigare Institutioner, Fysik.
    Johnson, Arne
    KTH, Tidigare Institutioner, Fysik.
    Klamra, Wlodzimierz
    KTH, Tidigare Institutioner, Fysik.
    Cederkäll, Joakim
    KTH, Tidigare Institutioner, Fysik.
    Devlin, M
    Elson, J
    LaFosse, R
    Lerma, F
    Sarantites, G
    Tomov, V
    Hausmann, M
    Jungclaus, A
    Napoli, R
    Carpenter, P
    Janssens, F
    Kondev, G
    Lauritsen, T
    Lister, J
    Seweryniak, D
    Wiedenhoever, I
    Clark, M
    Fallon, P
    Lee, Y
    Macchiavelli, O
    Macleod, W
    Superdeformation in 91Tc2000Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 492, nr 3-4, s. 245-253Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A high-spin rotational band with 11 gamma -ray transitions has barn observed in Tc-91. The dynamical moment of inertia as well as the transition quadrupole moment of 8.1(-1.4)(+1.9) eb measured for this band show the characteristics of a superdeformed band. However, the shape is more elongated than in the neighbouring A = 80-90 superdeformed nuclei. Theoretical interpretations of the band within the cranked Strutinsky approach based on two different Woods-Saxon potential parameterisations are presented. Even though an unambiguous configuration assignment proved difficult, both calculations indicate a larger deformation and at least three additional high-N intruder orbitals occupied compared to the lighter SD nuclei. (C) 2000 Elsevier Science B.V. All rights reserved.

  • 254. Jackson, P. D.
    et al.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sidebo, P. Edvin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L.
    et al.,
    Search for charged Higgs bosons produced in association with a top quark and decaying via H± → τν using pp collision data recorded at s=13 TeV by the ATLAS detector2016Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 759, s. 555-574Artikkel i tidsskrift (Fagfellevurdert)
  • 255. Jacobsson, Björn
    et al.
    Ohlsson, Tommy
    KTH, Tidigare Institutioner, Fysik.
    Snellman, Håkan
    KTH, Tidigare Institutioner, Fysik.
    Winter, Walter
    Effects of random matter density fluctuations on the neutrino oscillation transition probabilities in the Earth2002Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 532, nr 04-mar, s. 259-266Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this Letter, we investigate the effects of random fluctuations of the Earth matter density for long baselines on the neutrino oscillation transition probabilities. We especially identify relevant parameters characterizing the matter density noise and calculate their effects by averaging over statistical ensembles of a large number of matter density profiles. For energies and baselines appropriate to neutrino factories, absolute errors on the relevant appearance probabilities are at the level of \DeltaP(alphabeta)\ similar to 10(-4) (with perhaps \P-mue similar to 1% for neutrinos), whereby a modest improvement in understanding of the geophysical data should render such effects unimportant.

  • 256. Jimenez, Jose Beltran
    et al.
    Koivisto, Tomi S.
    KTH, Centra, Nordic Institute for Theoretical Physics NORDITA.
    Spacetimes with vector distortion: Inflation from generalised Weyl geometry2016Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 756, s. 400-404Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Spacetime with general linear vector distortion is introduced. Thus, the torsion and the nonmetricity of the affine connection are assumed to be proportional to a vector field (and not its derivatives). The resulting two-parameter family of non-Riemannian geometries generalises the conformal Weyl geometry and some other interesting special cases. Taking into account the leading nonlinear correction to the Einstein-Hilbert action results uniquely in the one-parameter extension of the Starobinsky inflation known as the alpha-attractor. The most general quadratic curvature action introduces, in addition to the canonical vector kinetic term, novel ghost-free vector-tensor interactions.

  • 257. Joss, D. T.
    et al.
    Darby, I. G.
    Page, R. D.
    Uusitalo, J.
    Eeckhaudt, S.
    Grahn, T.
    Greenlees, P. T.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Leino, M.
    Leppänen, A. -P
    Nyman, M.
    Pakarinen, J.
    Rahkila, P.
    Sarén, J.
    Scholey, C.
    Steer, A.
    Cannon, A. J.
    Stevenson, P. D.
    Al-Khalili, J. S.
    Ertürk, S.
    Venhart, M.
    Gall, B.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Simpson, J.
    Probing the limit of nuclear existence: Proton emission from Re-1592006Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 641, nr 1, s. 34-37Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The observation of the new nuclide Re-159(75)84 provides important insights into the evolution of single-particle structure and the mass surface in heavy nuclei beyond the proton drip line. This nuclide, 26 neutrons away from the nearest stable rhenium isotope, was synthesised in the reaction Cd-106(Ni-58, p4n) and identified via its proton radioactivity using the RITU gas-filled separator and the GREAT focal-plane spectrometer. Comparisons of the measured proton energy (E-p = 1805 +/- 20 keV) and decay half-life (t(1/2) = 21 +/- 4 mu s) with values calculated using the WKB method indicate that the proton is emitted from an h(11/2) state. The implications of these results for future experimental investigations into even more proton unbound nuclei using in-flight separation techniques are considered.

  • 258. Joss, D. T.
    et al.
    Page, R. D.
    Herzán, A.
    Donosa, L.
    Uusitalo, J.
    Carroll, R. J.
    Darby, I. G.
    Andgren, Karin
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Eeckhaudt, S.
    Grahn, T.
    Greenlees, P. T.
    Hadinia, Baharak
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Jakobsson, Ulrika
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik. University of Jyvaskyla, Finland.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Leino, M.
    Leppanen, A. -P
    Nyman, M.
    O'Donnell, D.
    Pakarinen, J.
    Rahkila, P.
    Sandzelius, M.
    Sarén, J.
    Scholey, C.
    Seweryniak, D.
    Simpson, J.
    Sorri, J.
    Spectroscopy at the two-proton drip line: Excited states in 158W2017Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 772, s. 703-707Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Excited states have been identified in the heaviest known even-Z N=84 isotone 158W, which lies in a region of one-proton emitters and the two-proton drip line. The observation of γ-ray transitions feeding the ground state establishes the excitation energy of the yrast 6+ state confirming the spin-gap nature of the α-decaying 8+ isomer. The 8+ isomer is also expected to be unbound to two-proton emission but no evidence for this decay mode was observed. An upper limit for the two-proton decay branch has been deduced as b2p≤ 0.17% at the 90% confidence level. The possibility of observing two-proton emission from multiparticle isomers in nearby nuclides is considered.

  • 259. King, S L
    et al.
    Simpson, J
    Page, R D
    Amzal, N
    Bäck, Torbjörn
    Cederwall, Bo
    Cocks, J F C
    Cullen, D M
    Greenlees, P T
    Harder, M K
    Helariutta, K
    Jones, P
    Julin, R
    Juutinen, S
    Kankaanpaa, H
    Keenan, A
    Kettunen, H
    Kuusiniemi, P
    Leino, M
    Lemmon, R
    Muikku, M
    Savelius, A
    Uusitalo, J
    Van Isacker, P
    First observation of excited states in the neutron deficient nuclei (PT)-P-168 and Pt-1701998Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 443, nr 1-4, s. 82-88Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Excited states have been observed for the first time in (XPt)-X-168 and Pt-170 using the alpha-decay recoil-tagging technique. The trend of decreasing deformation moving away from the N = 104 mid-shell continues far Pt-170 but the structure of Pt-168 is significantly different. The low spin level energy systematics in Pt168-184 are presented and discussed within the framework of the interacting boson model. (C) 1998 Elsevier Science B.V. All rights reserved.

  • 260.
    Konstandin, Thomas
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik.
    Ohlsson, Tommy
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik.
    The effective matter potential for highly relativistic neutrinos2006Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 634, nr 03-feb, s. 267-271Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigate matter effects on highly relativistic neutrinos. The self-energy of neutrinos is determined in an electron or neutrino background taking into account resonance and finite width effects of the gauge bosons. We find minor changes compared to the formerly used formula for the propagator function and large deviations of the effective width from the decay width of the gauge bosons considering higher moments of the electron or neutrino distribution function.

  • 261. LAFOSSE, DR
    et al.
    HUA, PF
    SARANTITES, DG
    BAKTASH, C
    AKOVALI, YA
    BRINKMAN, M
    Cederwall, Bo
    CRISTANCHO, F
    DORING, J
    GROSS, CJ
    JIN, HQ
    KOROLIJA, M
    LANDULFO, E
    LEE, IY
    MACCHIAVELLI, AO
    MAIER, MR
    RATHBUN, W
    SALADIN, JX
    STRACENER, DW
    TABOR, SL
    VANDERMOLLEN, A
    WERNER, TR
    CHARACTERIZATION OF THE FIRST SUPERDEFORMED BAND IN THE A-APPROXIMATE-TO-80 REGION1995Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 354, nr 1-2, s. 34-40Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The recently discovered superdeformed band in one of the strontium isotopes has been identified as belonging to Sr-83 from a study with the Gammasphere array and the Microball charged-particle detector system. From its decay pattern, a spin of (81 +/- 2)/2 ($) over bar h is deduced for the highest level of this band. Evidence for very fast transition rates and agreement of the characteristics of this band with the theoretical predictions establish the yrast superdeformed nature of this band in Sr-83.

  • 262.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    (3+1)-Dimensional Schwinger Terms and Non-commutative Geometry1994Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 338, s. 241-248Artikkel i tidsskrift (Fagfellevurdert)
  • 263.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Gauge Theories on a Cylinder1992Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 296, s. 117-120Artikkel i tidsskrift (Fagfellevurdert)
  • 264.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Gribov ambiguity and non-trivial vacuum structure of gauge theories on a cylinder1993Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 303, s. 303-307Artikkel i tidsskrift (Fagfellevurdert)
  • 265.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Novel integrable spin-particle models from gauge theories on a cylinder1998Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 429, s. 336-342Artikkel i tidsskrift (Fagfellevurdert)
  • 266.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    QCD(1+1) with massless quarks and gauge covariant Sugawara construction1994Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 341, s. 195-204Artikkel i tidsskrift (Fagfellevurdert)
  • 267.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Strong coupling gauge theory, quantum spin systems and the spontaneous breaking of chiral symmetry1992Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 297, s. 175-180Artikkel i tidsskrift (Fagfellevurdert)
  • 268.
    Langmann, Edwin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Matematisk fysik. KTH, Skolan för teknikvetenskap (SCI), Fysik, Kondenserade materiens teori.
    Towards a string representation of infrared SU(2) Yang-Mills theory1999Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 463, s. 252-256Artikkel i tidsskrift (Fagfellevurdert)
  • 269.
    Langmann, Edwin
    et al.
    KTH, Tidigare Institutioner                               , Fysik.
    Szabo, R. J.
    Duality in scalar field theory on noncommutative phase spaces2002Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 533, nr 02-jan, s. 168-177Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We describe a novel duality symmetry of Phi(2n)(4)-theory defined on noncommutative Euclidean space and with noncommuting momentum coordinates. This duality acts on the fields by Fourier transformation and scaling. It is an extension, to interactions defined with a star-product, of that which arises in quantum field theories of non-interacting scalar particles coupled to a constant background electromagnetic field. The dual models are in general of the same original form but with transformed coupling parameters, while in certain special cases all parameters are essentially unchanged. Using a particular regularization we show, to all orders of perturbation theory, that this duality also persists at the quantum level. We also point out various other properties of this class of noncommutative field theories.

  • 270.
    Langmann, Edwin
    et al.
    KTH, Tidigare Institutioner                               , Fysik.
    Szabo, R. J.
    Zarembo, K.
    Exact solution of noncommutative field theory in background magnetic fields2003Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 569, nr 02-jan, s. 95-101Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We obtain the exact nonperturbative solution of a scalar field theory defined on a space with noncommuting position and momentum coordinates. The model describes nonlocally interacting charged particles in a background magnetic field. It is an exactly solvable quantum field theory which has nontrivial interactions only when it is defined with a finite ultraviolet cutoff. We propose that small perturbations of this theory can produce solvable models with renormalizable interactions.

  • 271. Lowe, David A.
    et al.
    Thorlacius, Larus
    KTH, Centra, Nordic Institute for Theoretical Physics NORDITA. Stockholm University, Sweden.
    Black hole complementarity: The inside view2014Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 737, s. 320-324Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Within the framework of black hole complementarity, a proposal is made for an approximate interior effective field theory description. For generic correlators of local operators on generic black hole states, it agrees with the exact exterior description in a region of overlapping validity, up to corrections that are too small to be measured by typical infalling observers.

  • 272. Magierski, P.
    et al.
    Wyss, Ramon
    KTH, Tidigare Institutioner                               , Fysik.
    Selfconsistent effective interactions and symmetry restoration2000Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 486, nr 02-jan, s. 54-60Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present paper clarifies on the quantum level the concept of selfconsistent interactions and symmetry restoration by means of the generalized scaling fields. It is shown that the concept of symmetry restoration in RPA order fan directly be related to the concept of selfconsistent interations. The difference of the two methods originates from the coupling of the kinetic energy operator to the perturbing field. The presented method is superior to the semiclassical approach. It also yields, in its limiting case, the multipole-multipole effective interaction.

  • 273.
    Malinsky, Michal
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Ohlsson, Tommy
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Xing, Zhi-zhong
    Zhang, He
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Non-unitary neutrino mixing and CP violation in the minimal inverse seesaw model2009Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 679, nr 3, s. 242-248Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We propose a simplified version of the inverse seesaw model, in which only two pairs of the gauge-singlet neutrinos are introduced, to interpret the observed neutrino mass hierarchy and lepton flavor mixing at or below the TeV scale. This "minimal" inverse seesaw scenario (MISS) is technically natural and experimentally testable. In particular, we show that the effective parameters describing the non-unitary neutrino mixing matrix are strongly correlated in the MISS, and thus, their upper bounds can be constrained by current experimental data in a more restrictive way. The Jarlskog invariants of non-unitary CP violation are calculated, and the discovery potential of such new CP-violating effects in the near detector of a neutrino factory is discussed.

  • 274.
    Melbéus, Henrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Merle, Alexander
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Ohlsson, Tommy
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Continuum photon spectrum from Z1Z1 annihilations in universal extra dimensions2012Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 706, nr 4-5, s. 329-332Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We calculate the continuum photon spectrum from the pair annihilation of a Z1 LKP in non-minimal universal extra dimensions. We find that, due to the preferred annihilation into W+ W- pairs, the continuum flux of collinear photons is relatively small compared to the standard case of the B1 as the LKP. This conclusion applies in particular to the spectral endpoint, where also the additional fermionic contributions are not large enough to increase the flux significantly. When searching for the line signal originating from Z1 Z1 annihilations, this is actually a perfect situation, since the continuum signal can be regarded as background to the smoking gun signature of a peak in the photon flux at an energy that is nearly equal to the mass of the dark matter particle. This signal, in combination with (probably) a non-observation of the continuum signal at lower photon energies, constitutes a perfect handle to probe the hypothesis of the Z1 LKP being the dominant component of the dark matter observed in the Universe.

  • 275.
    Melbéus, Henrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik. Royal Inst Technol KTH, Dept Theoret Phys, Sch Engn Sci, S-10691 Stockholm, Sweden..
    Merle, Alexander
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik. Royal Inst Technol KTH, Dept Theoret Phys, Sch Engn Sci, S-10691 Stockholm, Sweden..
    Ohlsson, Tommy
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik. Royal Inst Technol KTH, Dept Theoret Phys, Sch Engn Sci, S-10691 Stockholm, Sweden..
    Erratum to: Continuum photon spectrum from Z(1)Z(1) annihilations in universal extra dimensions2012Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 713, nr 3, s. 350-350Artikkel i tidsskrift (Fagfellevurdert)
  • 276.
    Melbéus, Henrik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Merle, Alexander
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Ohlsson, Tommy
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Higgs dark matter in UEDs: A good WIMP with bad detection prospects2012Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 715, nr 1-3, s. 164-169Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We study the first Kaluza-Klein excitation of the Higgs boson in universal extra dimensions as a dark matter candidate. The first-level Higgs boson could be the lightest Kaluza-Klein particle, which is stable due to the conservation of Kaluza-Klein parity, in non-minimal models where boundary localized terms modify the mass spectrum. We calculate the relic abundance and find that it agrees with the observed dark matter density if the mass of the first-level Higgs boson is slightly above 2 TeV, not considering coannihilations and assuming no relative mass splitting among the first-level Kaluza-Klein modes. In the case of coannihilations and a non-zero mass splitting, the mass of the first-level Higgs boson can range from 1 TeV to 4 TeV. We study also the prospects for detection of this dark matter candidate in direct as well as indirect detection experiments. Although the first-level Higgs boson is a typical weakly interacting massive particle, an observation in any of the conventional experiments is very challenging.

  • 277.
    Meyer, HO
    et al.
    Uppsala universitet, Institutionen för kärn- och partikelfysik.
    Knutson, LD
    Balewski, JT
    Daehnick, WW
    Doskow, J
    Haeberli, W
    Lorentz, B
    Pollock, RE
    Pancella, PV
    von, Przewoski B
    Rathmann, F
    Rinckel, T
    Saha, SK
    Schwartz, B
    Thorngren-Engblom, P
    Wellinghausen, A
    Wise, T
    Observation of a large longitudinal analyzing power in a nuclear reaction2000Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 480, nr 1-2, s. 7-11Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have measured the longitudinal analyzing power A(z) of the pp --> pp pi(0) reaction at 375 MeV bombarding energy. We find that for certain angle combinations of the outgoing particles the observed A(z) is as large as 0.3, demonstrating that sizeable lo

  • 278. NISIUS, D
    et al.
    JANSSENS, RVF
    FALLON, P
    CROWELL, B
    AHMAD, I
    BEAUSANG, CW
    CARPENTER, MP
    CEDERWALL, BO
    DALY, PJ
    DELEPLANQUE, MA
    DIAMOND, RM
    GASSMANN, D
    GRABOWSKI, ZW
    HENRY, RG
    KHOO, TL
    LAURITSEN, T
    LEE, IY
    MACCHIAVELLI, AO
    MAYER, RH
    STEPHENS, FS
    TWIN, PJ
    IDENTICAL SUPERDEFORMED BAND IN DY-151 - FURTHER EVIDENCE FOR THE PSEUDOSPIN COUPLING SCHEME1995Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 346, nr 1-2, s. 15-20Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One of the four new excited superdeformed bands found in Dy-151 is characterized by transition energies that lie midway between the gamma-ray energies of the yrast superdeformed band in Dy-152. This result adds significant new information on the issue of ''identical'' bands, as it confirms predictions based on the strong coupling model and the pseudospin coupling scheme.

  • 279.
    Oellers, D.
    et al.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Barion, L.
    Università di Ferrara and INFN, 44100 Ferrara, Italy.
    Barsov, S.
    St. Petersburg Nuclear Physics Institute, 188350 Gatchina, Russia.
    Bechstedt, U.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Benati, P.
    Università di Ferrara and INFN, 44100 Ferrara, Italy.
    Bertelli, S.
    Università di Ferrara and INFN, 44100 Ferrara, Italy.
    Chiladze, D.
    High Energy Physics Institute, Tbilisi State University, 0186 Tbilisi, Georgia.
    Ciullo, G.
    Università di Ferrara and INFN, 44100 Ferrara, Italy.
    Contalbrigo, M.
    INFN, Sezione di Ferrara, 44100 Ferrara, Italy.
    Dalpiaz, P.F.
    Università di Ferrara and INFN, 44100 Ferrara, Italy.
    Dietrich, J.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Dolfus, N.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Dymov, S.
    Physikalisches Institut II, Universität Erlangen-Nürnberg, 91058 Erlangen, Germany.
    Engels, R.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Erven, W.
    Jülich Center for Hadron Physics, 52425 Jülich, Germany.
    Garishvili, A.
    High Energy Physics Institute, Tbilisi State University, 0186 Tbilisi, Georgia.
    Gebel, R.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Goslawski, P.
    Institut für Kernphysik, Universität Münster, 48149 Münster, Germany.
    Grigoryev, K.
    St. Petersburg Nuclear Physics Institute, 188350 Gatchina, Russia.
    Hadamek, H.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Kacharava, A.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Khoukaz, A.
    Institut für Kernphysik, Universität Münster, 48149 Münster, Germany.
    Kulikov, A.
    Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, 141980 Dubna, Russia.
    Langenberg, G.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Lehrach, A.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Lenisa, P.
    Università di Ferrara and INFN, 44100 Ferrara, Italy.
    Lomidze, N.
    High Energy Physics Institute, Tbilisi State University, 0186 Tbilisi, Georgia.
    Lorentz, B
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Macharashvili, G.
    Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, 141980 Dubna, Russia.
    Maier, R.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Martin, S.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Merzliakov, S.
    Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, 141980 Dubna, Russia.
    Meshkov, I.N.
    Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, 141980 Dubna, Russia.
    Meyer, H.O.
    Physics Department, Indiana University, Bloomington, IN 47405, USA.
    Mielke, M.
    Institut für Kernphysik, Universität Münster, 48149 Münster, Germany.
    Mikirtychiants, M.
    St. Petersburg Nuclear Physics Institute, 188350 Gatchina, Russia.
    Mikirtychiants, S.
    St. Petersburg Nuclear Physics Institute, 188350 Gatchina, Russia.
    Nass, A.
    Physikalisches Institut II, Universität Erlangen-Nürnberg, 91058 Erlangen, Germany.
    Nekipelov, M.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Nikolaev, N.N.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Nioradze, M.
    High Energy Physics Institute, Tbilisi State University, 0186 Tbilisi, Georgia.
    d'Orsaneo, G.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Papenbrockj, M.
    Institut für Kernphysik, Universität Münster, 48149 Münster, Germany.
    Prasuhn, D.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Rathmann, F.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Sarkadi, J.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    R. Schleichert, R.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Smirnov, A.
    Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, 141980 Dubna, Russia.
    Seyfarth, H.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Sowinski, J.
    Physics Department, Indiana University, Bloomington, IN 47405, USA.
    Spoelgen, D.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Stancari, G.
    INFN, Sezione di Ferrara, 44100 Ferrara, Italy.
    Stancari, M.
    Università di Ferrara and INFN, 44100 Ferrara, Italy.
    Statera, M.
    Università di Ferrara and INFN, 44100 Ferrara, Italy.
    Steffens, E.
    Physikalisches Institut II, Universität Erlangen-Nürnberg, 91058 Erlangen, Germany.
    Stein, H.J.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Stockhorst, H.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Straatmann, H.
    Zentralabteilung Technologie, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Ströher, H.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Tabidze, M.
    High Energy Physics Institute, Tbilisi State University, 0186 Tbilisi, Georgia.
    Tagliente, G.
    INFN, Sezione di Bari, 70126 Bari, Italy.
    Thörngren Engblom, Pia
    Stockholms universitet, Fysikum.
    Trusov, S.
    Institut für Kern- und Hadronenphysik, Forschungszentrum Rossendorf, 01314 Dresden, Germany.
    Vasilyev, A.
    St. Petersburg Nuclear Physics Institute, 188350 Gatchina, Russia.
    Weidemann, Chr.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Welsch, D.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Wieder, P.
    Institut für Kernphysik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Wüstner, P.
    Zentralinstitut für Elektronik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
    Zupranski, P.
    Department of Nuclear Reactions, Andrzej Soltan, Institute for Nuclear Studies, 00-681 Warsaw, Poland.
    Polarizing a stored proton beam by spin flip?2009Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 674, nr 4-5, s. 269-275Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We discuss polarizing a proton beam in a storage ring, either by selective removal or by spin flip of the stored ions. Prompted by recent, conflicting calculations, we have carried out a measurement of the spin-flip cross section in low-energy electron–proton scattering. The experiment uses the cooling electron beam at COSY as an electron target. The measured cross sections are too small for making spin flip a viable tool in polarizing a stored beam. This invalidates a recent proposal to use co-moving polarized positrons to polarize a stored antiproton beam.

  • 280.
    Ohlsson, Tommy
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Bimaximal fermion mixing from the quark and leptonic mixing matrices2005Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 622, nr 02-jan, s. 159-164Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this Letter. we show how the mixing angles of the standard parameterization add when multiplying the quark and leptonic mixing matrices. i.e., we derive explicit sum rules for the quark and leptonic mixing angles. In this connection, we also discuss other recently proposed sum rules for the mixing angles assuming bimaximal fermion mixing. In addition, we find that the present experimental and phenomenological data of the mixing angles naturally fulfill our sum rules, and thus, give rise to bilarge or bimaximal fermion mixing.

  • 281.
    Ohlsson, Tommy
    KTH, Tidigare Institutioner, Fysik.
    Effects and influences on neutrino oscillations due to a thin density layer perturbation added to a matter density profile2001Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 522, nr 04-mar, s. 280-286Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this Letter, we show the effects on the transition probabilities for neutrino oscillations due to a thin constant density layer perturbation added to an arbitrary matter density profile, In the case of two neutrino flavors, we calculate the effects both analytically and numerically, whereas in the case of three neutrino flavors, we perform the studies purely numerically. As an realistic example we consider the effects of the Earth's atmosphere when added to the Earth's matter density profile on the neutrino oscillation transition probabilities for atmospheric neutrinos.

  • 282.
    Ohlsson, Tommy
    KTH, Tidigare Institutioner, Fysik.
    Equivalence between Gaussian averaged neutrino oscillations and neutrino decoherence2001Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 502, nr 04-jan, s. 159-166Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this Letter, we show that a Gaussian averaged neutrino oscillation model is equivalent to a neutrino decoherence model. Without loss of generality, the analysis is performed with two neutrino flavors. We also estimate the damping (or decoherence) parameter for atmospheric neutrinos and compare it to earlier obtained results.

  • 283.
    Ohlsson, Tommy
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Popa, Christoph
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Zhang, He
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Non-unitarity of the leptonic mixing matrix in the TeV-scale type-I seesaw model2010Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 692, nr 4, s. 257-260Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The non-unitarity effects in leptonic flavor mixing are regarded as one of the generic features of the type-1 seesaw model. Therefore, we explore these effects in the TeV-scale type-1 seesaw model, and show that there exist non-trivial correlations among the non-unitarity parameters, stemming from the typical flavor structure of the low-scale seesaw model. In general, it follows from analytical discussions and numerical results that all the six non-unitarity parameters are related to three model parameters, while the widely studied parameters eta(e tau) and eta(mu tau) cannot be phenomenologically significant simultaneously.

  • 284.
    Ohlsson, Tommy
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Riad, Stella
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Running of neutrino parameters and the Higgs self-coupling in a six-dimensional UED model2013Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 718, nr 3, s. 1002-1007Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigate a six-dimensional universal extra-dimensional model in the extension of an effective neutrino mass operator. We derive the β-functions and renormalization group equations for the Yukawa couplings, the Higgs self-coupling, and the effective neutrino mass operator in this model. Especially, we focus on the renormalization group running of physical parameters such as the Higgs self-coupling and the leptonic mixing angles. The recent measurements of the Higgs boson mass by the ATLAS and CMS Collaborations at the LHC as well as the current three-flavor global fits of neutrino oscillation data have been taken into account. We set a bound on the six-dimensional model, using the vacuum stability criterion, that allows five Kaluza-Klein modes only, which leads to a strong limit on the cutoff scale. Furthermore, we find that the leptonic mixing angle θ12 shows the most sizeable running, and that the running of the angles θ13 and θ23 are negligible. Finally, it turns out that the findings in this six-dimensional model are comparable with what is achieved in the corresponding five-dimensional model, but the cutoff scale is significantly smaller, which means that it could be detectable in a closer future.

  • 285.
    Ohlsson, Tommy
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Schwetz, Thomas
    Zhang, He
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Non-standard neutrino interactions in the Zee-Babu model2009Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 681, nr 3, s. 269-275Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigate non-standard neutrino interactions (NSIs) in the Zee-Babu model. The size of NSIs predicted by this model is obtained from a full scan over the parameter space. taking into account constraints from low-energy experiments such as searches for lepton flavor violation (LFV) and the requirement to obtain a viable neutrino mass matrix. The dependence on the scale of new physics as well as on the type of the neutrino mass hierarchy is discussed. We find that NSIs at the source of a future neutrino factory may be at an observable level in the nu(e) -> nu(tau) and/or nu(mu) -> nu(tau) channels. In particular, if the doubly charged scalar of the model has a mass in reach of the LHC and if the neutrino mass hierarchy is inverted, a highly predictive scenario is obtained with observable signals at the LHC, in upcoming neutrino oscillation experiments, in LFV processes, and for NSIs at a neutrino factory.

  • 286.
    Ohlsson, Tommy
    et al.
    KTH, Tidigare Institutioner, Fysik.
    Seidl, Gerhart
    Bilarge leptonic mixing from Abelian horizontal symmetries2002Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 537, nr 02-jan, s. 95-102Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We construct and present a model for leptonic mixing based on higher-dimensional operators, using the Froggatt-Nielsen mechanism. and Abelian horizontal symmetries (flavor symmetries) of continuous and discrete type. Our model naturally yields bilarge leptonic mixing. coming from both the charged leptons and the neutrinos, and an inverted neutrino mass hierarchy spectrum. The obtained values of the parameters, i.e.. the leptonic mixing parameters and the neutrino mass squared differences, are all consistent with the atmospheric neutrino data and the Mikheyev-Smirnov-Wolfenstein large mixing angle solution for the solar neutrino problem.

  • 287.
    Ohlsson, Tommy
    et al.
    KTH, Tidigare Institutioner, Fysik.
    Snellman, Håkan
    KTH, Tidigare Institutioner, Fysik.
    Neutrino oscillations with three flavors in matter: Applications to neutrinos traversing the earth2000Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 474, nr 1-2, s. 153-162Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Analytic formulas are presented for three flavor neutrino oscillations in matter in the plane wave approximation. We calculate in particular the time evolution operator in both mass and flavor bases. We also find the transition probabilities expressed as functions of the vacuum mass squared differences, the vacuum mixing angles, and the matter density parameter. The application of this to neutrino oscillations for both atmospheric and long baseline neutrinos in a mantle-core-mantle step function model of the Earth's matter density profile is discussed.

  • 288.
    Ohlsson, Tommy
    et al.
    KTH, Tidigare Institutioner, Fysik.
    Winter, Walter
    Reconstruction of the Earth's matter density profile using a single neutrino baseline2001Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 512, nr 04-mar, s. 357-364Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this Letter, we show numerically that a symmetric Earth matter density profile can, in principle, be reconstructed from a single baseline energy spectrum up to a certain precision. For the numerical evaluations in the high-dimensional parameter space we use a genetic algorithm.

  • 289.
    Ohlsson, Tommy
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Zhang, He
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Non-standard interaction effects at reactor neutrino experiments2009Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 671, nr 1, s. 99-104Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We study non-standard interactions (NSIs) at reactor neutrino experiments, and in particular, the mimicking effects on theta(13). We present generic formulas for oscillation probabilities including NSIs from sources and detectors. Instructive mappings between the fundamental leptonic mixing parameters and the effective leptonic mixing parameters are established. In addition, NSI corrections to the mixing angles theta(13) and theta(12) are discussed in detailed. Finally, we show that, even for a vanishing theta(13), all Oscillation phenomenon may still be observed ill future short baseline reactor neutrino experiments, such as Double Chooz and Daya Bay, due to the existences of NSIs.

  • 290.
    Ohlsson, Tommy
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Zhang, He
    Zhou, Shun
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Teoretisk partikelfysik.
    Nonstandard interaction effects on neutrino parameters at medium-baseline reactor antineutrino experiments2014Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 728, s. 148-155Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Precision measurements of leptonic mixing parameters and the determination of the neutrino mass hierarchy are the primary goals of the forthcoming medium-baseline reactor antineutrino experiments, such as JUNO and RENO-50. In this work, we investigate the impact of nonstandard neutrino interactions (NSIs) on the measurements of {sin(2) theta(12), Delta m(21)(2)} and {sin(2) theta(13), Delta m(31)(2)}. and on the sensitivity to the neutrino mass hierarchy, at the medium-baseline reactor experiments by assuming a typical experimental setup. It turns out that the true mixing parameter sin(2) theta(12) can be excluded at a more than 3 sigma level if the NSI parameter epsilon(e mu), or epsilon(e tau), is as large as 2% in the most optimistic case. However, the discovery reach of NSI effects has been found to be small, and depends crucially on the CP-violating phases. Finally, we show that NSI effects could enhance or reduce the discrimination power of the JUNO and RENO-50 experiments between the normal and inverted neutrino mass hierarchies.

  • 291.
    Ong, Yen Chin
    KTH, Centra, Nordic Institute for Theoretical Physics NORDITA. Center for Gravitation and Cosmology, College of Physical Science and Technology, Yangzhou University, Yangzhou 225009, China; School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
    GUP-corrected black hole thermodynamics and the maximum force conjecture2018Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 785, s. 217-220Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We show that thermodynamics for an asymptotically flat Schwarzschild black hole leads to a force of magnitude c4/(2G). This remains true if one considers the simplest form of correction due to the generalized uncertainty principle. We comment on the maximum force conjecture, the subtleties involved, as well as the discrepancies with previous results in the literature. 

  • 292. Pellegri, L.
    et al.
    Bracco, A.
    Crespi, F. C. L.
    Leoni, S.
    Camera, F.
    Lanza, E. G.
    Kmiecik, M.
    Maj, A.
    Avigo, R.
    Benzoni, G.
    Blasi, N. a
    Boiano, C.
    Bottoni, S.
    Brambilla, S.
    Ceruti, S.
    Giaz, A.
    Million, B.
    Morales, A. I.
    Nicolini, R.
    Vandone, V.
    Wieland, O.
    Bazzacco, D.
    Bednarczyk, P.
    Bellato, M.
    Birkenbach, B.
    Bortolato, D.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Charles, L.
    Ciemala, M.
    De Angelis, G.
    Desesquelles, P.
    Eberth, J.
    Farnea, E.
    Gadea, A.
    Gernhaeuser, R.
    Gorgen, A.
    Gottardo, A.
    Grebosz, J.
    Hess, H.
    Isocrate, R.
    Jolie, J.
    Judson, D.
    Jungclaus, A.
    Karkour, N.
    Krzysiek, M.
    Litvinova, E.
    Lunardi, S.
    Mazurek, K.
    Mengoni, D.
    Michelagnoli, C.
    Menegazzo, R.
    Molini, P.
    Napoli, D. R.
    Pullia, A.
    Quintana, B.
    Recchia, F.
    Reiter, P.
    Salsac, M. D.
    Siebeck, B.
    Siem, S.
    Simpson, J.
    Soderstrom, P. -A
    Stezowski, O.
    Theisen, Ch.
    Ur, C.
    Dobon, J. J. Valiente
    Zieblinski, M.
    Pygmy dipole resonance in Sn-124 populated by inelastic scattering of O-172014Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 738, s. 519-523Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The gamma decay from the high-lying states of Sn-124 was measured using the inelastic scattering of O-17 at 340 MeV. The emitted gamma rays were detected with high resolution with the AGATA demonstrator array and the scattered ions were detected in two segmented Delta E-E silicon telescopes. The angular distribution was measured both for the gamma rays and the scattered O-17 ions. An accumulation of E1 strength below the particle threshold was found and compared with previous data obtained with (gamma,gamma') and (alpha,alpha'gamma) reactions. The present results of elastic scattering, and excitation of E2 and E1 states were analysed using the DWBA approach. From this comprehensive description the isoscalar component of the 1-excited states was extracted. The obtained values are based on the comparison of the data with DWBA calculations including a form factor deduced using a microscopic transition density.

  • 293. Procter, M. G.
    et al.
    Cullen, D. M.
    Scholey, C.
    Ruotsalainen, P.
    Angus, L.
    Bäck, Torbjörn
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Dewald, A.
    Fransen, C.
    Grahn, T.
    Greenlees, P. T.
    Hackstein, M.
    Jakobsson, U.
    Jones, P. M.
    Julin, R.
    Juutinen, S.
    Ketelhut, S.
    Leino, M.
    Liotta, Roberto
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Lumley, N. M.
    Mason, P. J. R.
    Nieminen, P.
    Nyman, M.
    Pakarinen, J.
    Pissulla, T.
    Peura, P.
    Rahkila, P.
    Revill, J.
    Rigby, S. V.
    Rother, W.
    Sandzelius, M.
    Saren, J.
    Sorri, J.
    Taylor, M. J.
    Uusitalo, J.
    Wady, P.
    Qi, Chong
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Xu, F. R.
    Anomalous transition strength in the proton-unbound nucleus (109)(53)I562011Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 704, nr 3, s. 118-122Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A lifetime measurement has been made for the first excited 11/2(+) state in the proton-unbound nucleus (109)(53)I56 using the recoil-distance Doppler-shift method in conjunction with recoil-proton tagging. The experimental reduced transition probability is considerably smaller than the prediction of theoretical shell-model calculations using the CD-Bonn nucleon-nucleon potential. The discrepancy between the theoretical and experimental reduced transition strengths in this work most likely arises from the inability of the current shell-model calculations to accurately account for the behavior of the unbound nuclear states.

  • 294.
    Qi, Chong
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Double binding energy differences: Mean-field or pairing effect?2012Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 717, nr 4-5, s. 436-440Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this Letter we present a systematic analysis on the average interaction between the last protons and neutrons in atomic nuclei, which can be extracted from the double differences of nuclear binding energies. The empirical average proton-neutron interaction V-pn thus derived from experimental data can be described in a very simple form as the interplay of the nuclear mean field and the pairing interaction. It is found that the smooth behavior as well as the local fluctuations of the V-pn in even-even nuclei with N not equal Z are dominated by the contribution from the proton-neutron monopole interactions. A strong additional contribution from the isoscalar monopole interaction and isovector proton-neutron pairing interaction is seen in the V-pn for even-even N = Z nuclei and for the adjacent odd-A nuclei with one neutron or proton being subtracted.

  • 295.
    Qi, Chong
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Partial conservation of seniority and its unexpected influence on E2 transitions in g(9/2) nuclei2017Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 773, s. 616-619Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    There exist two uniquely defined v = 4 states in systems within a j = 9/2 subshell, which automatically conserve seniority and do not mix with other states. Here I show that the partial conservation of seniority plays an essential role in our understanding of the electric quadrupole transitions of the semimagic nuclei involving j = 9/2 subshells, including the long-lived 8(+) isomer in (94) Ru. The effects of configuration mixing from neighboring subshells on the structure of those unique states are analyzed. It is shown that a sharp transition from pure seniority coupling to a significant mixture between the v = 2 and v = 4 states may be induced by the cross-orbital non-diagonal interaction matrix elements. Such strong mixture is essential to explain the observed E2 transition properties of N = 50 isotones Pd-96 and Ru-94.

  • 296.
    Qi, Chong
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Andreyev, A. N.
    Huyse, M.
    Liotta, Roberto J.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Van Duppend, P.
    Wyss, Ramon
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    On the validity of the Geiger-Nuttall alpha-decay law and its microscopic basis2014Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 734, s. 203-206Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Geiger-Nuttall (GN) law relates the partial alpha-decay half-life with the energy of the escaping alpha particle and contains for every isotopic chain two experimentally determined coefficients. The expression is supported by several phenomenological approaches, however its coefficients lack a fully microscopic basis. In this paper we will show that: (1) the empirical coefficients that appear in the GN law have a deep physical meaning, and (2) the GN law is successful within the restricted experimental data sets available so far, but is not valid in general. We will show that, when the dependence of logarithm values of the alpha formation probability on the neutron number is not linear or constant, the GN law is broken. For the alpha decay of neutron-deficient nucleus Po-186, the difference between the experimental half-life and that predicted by the GN law is as large as one order of magnitude.

  • 297.
    Qi, Chong
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Xu, Zhen-Xiang
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Shell evolution and its indication on the isospin dependence of the spin-orbit splitting2013Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 724, nr 4-5, s. 247-252Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    The available experimental data on shell evolution indicate that the strength of the spin-orbit single-particle potential may be enhanced in neutron-rich nuclei. We observe that such a simple scheme destroys the harmonic oscillator magic numbers N = 8 and 20 and generates new magic numbers like N = 6, 14, 16, 32 and 34. The traditional magic numbers like N = 28 and 50 and N = 14 seen in O-22 are eroded in neutron-rich nuclei due to the sensitivity of larger-l orbitals to the depth of the central potential but they are more robust than the harmonic oscillator magic numbers. The N = 82 shell closure persists in neutron-rich nuclei while the previously proposed shell closures like N = 40 and 70 do not emerge. Both mechanisms contribute to enhancing the N = 56 and 90 gaps by splitting the 1d(5/2) and 0g(7/2) and the 0h(9/2) and 1f(7/2) orbitals.

  • 298.
    Ralet, D.
    et al.
    Univ Paris Saclay, Univ Paris Sud, CSNSM, CNRS IN2P3, F-91405 Orsay, France.;CEA DRF CNRS IN2P3, GANIL, Bd Henri Becquerel,BP 55027, F-14076 Caen, France..
    Cederwall, Bo
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Wieland, O.
    Inst Nazl Fis Nucl, I-20133 Milan, Italy..
    Evidence of octupole-phonons at high spin in Pb-2072019Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 797, artikkel-id UNSP 134797Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A lifetime measurement of the 19/2(-) state in Pb-207 has been performed using the Recoil Distance Doppler-Shift (RDDS) method. The nuclei of interest were produced in multi-nucleon transfer reactions induced by a Pb-208 beam impinging on a Mo-100 enriched target. The beam-like nuclei were detected and identified in terms of their atomic mass number in the VAMOS++ spectrometer while the prompt gamma rays were detected by the AGATA tracking array. The measured large reduced transition probability B(E3, 19/2(-) -> 13/2(+)) = 40(8) W.u. is the first indication of the octupole phonon at high spin in Pb-207. An analysis in terms of a particle-octupole-vibration coupling model indicates that the measured B(E3) value in Pb-207 is compatible with the contributions from single-phonon and single particle E3 as well as E3 strength arising from the double-octupole-phonon 6(+) state, all adding coherently. A crucial aspect of the coupling model, namely the strong mixing between single-hole and the phonon-hole states, is confirmed in a realistic shell-model calculation. Crown Copyright B.V.

  • 299.
    Satula, Wojtek
    et al.
    KTH, Tidigare Institutioner                               , Fysik.
    Wyss, Ramon
    KTH, Tidigare Institutioner                               , Fysik.
    Comments on the nuclear symmetry energy2003Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 572, nr 3-4, s. 152-158Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    According to standard textbooks, the nuclear symmetry energy originates from the kinetic energy and the interaction itself. We argue that this view requires certain modifications and propose a different scenario. We ascribe the physical origin of the kinetic term to the discreteness of fermionic levels of, in principle arbitrary binary fermionic systems, and relate its mean value directly to the average level density. Physically it connects this part also to the isoscalar interaction which, at least in self-bound systems- like atomic nuclei, decides upon the spatial dimensions of the system. For the general case of binary fermionic systems possible external confining potentials as well as specific boundary conditions will contribute to this part. The reliability of this concept is verified using self-consistent Skyrme-Hartree-Fock calculations.

  • 300. Seliverstov, M. D.
    et al.
    Cocolios, T. E.
    Dexters, W.
    Andreyev, A. N.
    Antalic, S.
    Barzakh, A. E.
    Bastin, B.
    Buescher, J.
    Darby, I. G.
    Fedorov, D. V.
    Fedoseyev, V. N.
    Flanagan, K. T.
    Franchoo, S.
    Fritzsche, S.
    Huber, G.
    Huyse, M.
    Keupers, M.
    Koester, U.
    Kudryavtsev, Yu.
    Marsh, B. A.
    Molkanov, P. L.
    Page, R. D.
    Sjödin, Marica
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Stefan, I.
    Van de Walle, J.
    Van Duppen, P.
    Venhart, M.
    Zemlyanoy, S. G.
    Charge radii of odd-A Po191-211 isotopes2013Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 719, nr 4-5, s. 362-366Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Isotope shifts have been measured for the odd-A polonium isotopes Po191-211 and changes in the nuclear mean square charge radii delta < r(2 >) have been deduced. The measurements were performed at CERN-ISOLDE using the in-source resonance-ionization spectroscopy technique. The combined analysis of these data and our recent results for even-A polonium isotopes indicates an onset of deformation already at Po-197,Po-198, when going away from stability. This is significantly earlier than was suggested by previous theoretical and experimental studies of the polonium isotopes. Moreover and in contrast to the mercury isotopes, where a strong odd-even staggering of the charge radii of the ground states was observed by approaching the neutron mid-shell at N = 104, no such effect is present in polonium down to Po-191. Consequently the charge radii of both isomeric and ground states of the odd-A polonium isotopes follow the same trend as the even-A isotopes.

34567 251 - 300 of 309
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