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Nuclear Theory·nucl-th

Monday·February 23, 2015

8 papers—4 primary·4 cross-listed

All8Primary4Cross-lists4
  1. 01

    [Submitted on 19 Feb 2015]

    Quarkonium formation time in relativistic heavy-ion collisions

    Taesoo Song🇩🇪 · Che Ming Ko🇺🇸 · Su Houng Lee🇰🇷

    We calculate the quarkonium formation time in relativistic heavy-ion collisions from the space-time correlator of heavy quark vector currents in a hydrodynamics background with the initial nonequilibrium stage expanding only in the longitudinal direction. Using in-medium quarkonia properties determined with the heavy quark potential taken to be the free energy from lattice calculations and the fact that quarkonia can only be formed below their dissociation temperatures due to color screening, we find that (1S), (2S), (3S), and are formed, respectively, at 1.2, 6.6, 8.8, 5.8, and 11.0 fm/c after the quark pair are produced in central Au+Au collisions at the top energy of Relativistic Heavy Ion Collider (RHIC), and these times become shorter in semi-central collisions. We further show, as an example, that including the effect of formation time enhances appreciably the survivability of (1S) in the produced hot dense matter.

    Comments:
    6 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1502.05734 [pdf]
    PRC(2015)·19 citations
  2. 02

    [Submitted on 20 Feb 2015]

    Shell-model study of quadrupole collectivity in light tin isotopes

    L. Coraggio🇮🇹 · A. Covello🇮🇹 · A. Gargano🇮🇹 · N. Itaco🇮🇹 · T. T. S. Kuo🇺🇸

    A realistic shell-model study is performed for neutron-deficient tin isotopes up to mass A=108. All shell-model ingredients, namely two-body matrix elements, single-particle energies, and effective charges for electric quadrupole transition operators, have been calculated by way of the many-body perturbation theory, starting from a low-momentum interaction derived from the high-precision CD-Bonn free nucleon-nucleon potential. The focus has been put on the enhanced quadrupole collectivity of these nuclei, which is testified by the observed large B(E2;0+ -> 2+)s. Our results evidence the crucial role played by the Z=50 cross-shell excitations that need to be taken into account explicitly to obtain a satisfactory theoretical description of light tin isotopes. We find also that a relevant contribution comes from the calculated neutron effective charges, whose magnitudes exceed the standard empirical values. An original double-step procedure has been introduced to reduce effectively the model space in order to overcome the computational problem.

    Comments:
    6 pages, 6 figures, 2 tables
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1502.05822 [pdf]
    PRC(2015)·38 citations
  3. 03

    [Submitted on 20 Feb 2015]

    Gamow-Teller properties of the double beta-decay partners 116Cd(Sn) and 150Nd(Sm)

    D. Navas-Nicolas · P. Sarriguren

    The two Gamow-Teller (GT) branches connecting the double-beta decay partners (116Cd, 116Sn) and (150Nd, 150Sm) with the intermediate nuclei 116In and 150Pm are studied within a microscopic approach based on a deformed proton-neutron quasiparticle random-phase approximation built on a Skyrme selfconsistent mean field with pairing correlations and spin-isospin residual forces. The results are compared with the experimental GT strength distributions extracted from charge-exchange reactions. Combining the two branches, the nuclear matrix elements for the two-neutrino double-beta decay are evaluated and compared to experimental values derived from the measured half-lives.

    Comments:
    10 pages, 16 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1502.05889 [pdf]
    PRC(2015)·10 citations
  4. 04

    [Submitted on 20 Feb 2015]

    Benchmarking Nuclear Fission Theory

    G.F. Bertsch · W. Loveland · W. Nazarewicz · P. Talou

    We suggest a small set of fission observables to be used as test cases for validation of theoretical calculations. The purpose is to provide common data to facilitate the comparison of different fission theories and models. The proposed observables are chosen from fission barriers, spontaneous fission lifetimes, fission yield characteristics, and fission isomer excitation energies.

    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1502.05985 [pdf]
    J.Phys.G(2015)·30 citations

Affiliations

first authorsco-authorsvia INSPIRE