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Nuclear Theory·nucl-th

Wednesday·September 16, 2015

8 papers—5 primary·3 cross-listed

All8Primary5Cross-lists3
  1. 01

    [Submitted on 14 Sept 2015]

    Probing mixed-spin pairing in heavy nuclei

    Brendan Bulthuis · Alexandros Gezerlis

    The nature of the nuclear pairing condensate is an active topic of investigation, especially as regards its neutron-proton versus identical-particle character, which manifests as the difference between spin-singlet and spin-triplet pairing. In this work, we probe the recently proposed mixed-spin pairing condensates, using a phenomenological Hamiltonian and Hartree-Fock-Bogoliubov theory along with the gradient method. In addition to improving the solution of the many-body problem, we have calculated a series of physical quantities and examined the robustness of the mixed-spin pairing state as the input Hamiltonian is modified. Overall, we find that even though the mixed-spin correlation energy is suppressed in comparison to earlier work, the new pairing behavior persists. We also discuss the possibility of directly probing the mixed-spin pairing phase.

    Comments:
    10 pages, 7 figures, 2 tables; v2 corresponds to the published version
    Subjects:
    Nuclear Theory (nucl-th); Superconductivity (cond-mat.supr-con)
    arXiv:
    1509.04295 [pdf]
    PRC(2016)·14 citations
  2. 02

    [Submitted on 15 Sept 2015]

    (Anti-)strangeness production in heavy-ion collisions

    Pierre Moreau🇩🇪 · Feng Li🇺🇸 · Che-Ming Ko🇺🇸 · Wolfgang Cassing🇩🇪 · Elena Bratkovskaya🇩🇪

    The production and dynamics of strange and antistrange hadrons in heavy-ion reactions from 3 GeV to 200 GeV is analyzed within the Parton-Hadron-String-Dynamics (PHSD) transport model. The PHSD results for strange baryon and antibaryon production are roughly consistent with the experimental data starting from upper SPS energies. Nevertheless, hadronic final state flavor-exchange reactions are important for the actual abundances, in particular at large rapidities where hadronic dynamics, parton fragmentation and string decay dominate. A striking disagreement between the PHSD results and the available data persists, however, for bombarding energies below 8 GeV where the strangeness production is significantly underestimated as in earlier HSD studies. This finding implies that the strangeness enhancement seen experimentally at FAIR/NICA energies cannot be attributed to a deconfinement phase transition or crossover but probably involves the approximate restoration of chiral symmetry in the hadronic phase.

    Comments:
    4 pages, 4 figures. To be published in the Proceedings of the 15th International Conference on Strangeness in Quark Matter (SQM2015), 6-11 July 2015, JINR, Dubna, Russia
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1509.04455 [pdf]
    J.Phys.Conf.Ser.(2016)·5 citations
  3. 03

    [Submitted on 15 Sept 2015]

    Microscopic coupled-channel calculations of nucleus-nucleus scattering including chiral three-nucleon-force effects

    Kosho Minomo · Michio Kohno · Kazuyuki Ogata

    We analyze O-O and C-C scattering with the microscopic coupled-channels method and investigate the coupled-channels and three-nucleon-force (3NF) effects on elastic and inelastic cross sections. In the microscopic coupled-channels calculation, the Melbourne g-matrix interaction modified according to the chiral 3NF effects is used. It is found that the coupled-channels and 3NF effects additively change both the elastic and inelastic cross sections. As a result, the coupled-channels calculation including the 3NF effects significantly improves the agreement between the theoretical results and the experimental data. The incident-energy dependence of the coupled-channels and 3NF effects is also discussed.

    Comments:
    5 pages, 2 figures, 1 table
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1509.04459 [pdf]
    PRC(2016)·20 citations
  4. 04

    [Submitted on 15 Sept 2015]

    Beta-decay study within multi-reference density functional theory and beyond

    M. Konieczka🇵🇱 · P. Baczyk🇵🇱 · W. Satula🇵🇱

    Pioneering study of Gamow-Teller (GT) and Fermi matrix elements (MEs) using no-core-configuration-interaction formalism rooted in multi-reference density functional theory is presented. After successful test performed for 6He -> 6Li beta-decay, the model is applied to compute MEs in the sd- and pf-shell T=1/2 mirror nuclei. The calculated GT MEs and the isospin-symmetry-breaking corrections to the Fermi branch are found to be in a very good agreement with shell-model predictions in spite of fundamental differences between these models concerning model space, treatment of correlations or inclusion of a core. This result indirectly supports the two-body current based scenarios behind the quenching of axial-vector coupling constant.

    Comments:
    5 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1509.04480 [pdf]
    PRC(2016)·23 citations
  5. 05

    [Submitted on 15 Sept 2015]

    One-nucleon transfer reactions and the optical potential

    F.M. Nunes🇺🇸 · A. Lovell🇺🇸 · A. Ross🇺🇸 · L.J. Titus🇺🇸 · R.J. Charity🇺🇸 · W.H. Dickhoff🇺🇸 · M.H. Mahzoon🇺🇸 · J. Sarich🇺🇸 · S. M. Wild🇺🇸

    We provide a summary of new developments in the area of direct reaction theory with a particular focus on one-nucleon transfer reactions. We provide a status of the methods available for describing (d,p) reactions. We discuss the effects of nonlocality in the optical potential in transfer reactions. The results of a purely phenomenological potential and the optical potential obtained from the dispersive optical model are compared; both point toward the importance of including nonlocality in transfer reactions explicitly. Given the large ambiguities associated with optical potentials, we discuss some new developments toward the quantification of this uncertainty. We conclude with some general comments and a brief account of new advances that are in the pipeline.

    Comments:
    7 pages, 5 figures, proceedings for the 14th International Conference on Nuclear Reaction Mechanisms, Varenna, June 2015
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1509.04700 [pdf]
    0 citations

Affiliations

first authorsco-authorsvia INSPIRE