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Nuclear Theory·nucl-th

Monday·November 9, 2020

6 papers—3 primary·3 cross-listed

All6Primary3Cross-lists3
  1. 01

    [Submitted on 6 Nov 2020]

    Variational approach with the superposition of the symmetry-restored quasi-particle vacua for nuclear shell-model calculations

    Noritaka Shimizu · Yusuke Tsunoda · Yutaka Utsuno · Takaharu Otsuka

    We propose a variational calculation scheme utilizing the superposition of the angular-momentum, parity, number projected quasiparticle vacua, that is especially suitable for applying to medium-heavy nuclei in shell-model calculations. We derive a formula for the energy variance with quasi-particle vacua and apply the energy-variance extrapolation to the present scheme for further precise estimation of the exact shell-model energy. The validity of the method is presented for the shell-model calculation of Ba in the model space. We also discuss the feasibility of this scheme in the case of the Nd in the and model space and demonstrate that its neutrinoless-double-beta-decay matrix element is obtained showing good convergence.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2011.03157 [pdf]
    PRC(2021)·42 citations
  2. 02

    [Submitted on 6 Nov 2020]

    Properties of Isoscalar Giant Multipole Resonances in medium-heavy closed-shell nuclei: a semimicroscopic description

    M. L. Gorelik (1) · S. Shlomo (2, 3) · B. A. Tulupov (4) · M. H. Urin (5) ((1) Moscow Economic School, Moscow, Russia, (2) Cyclotron Institute, Texas A&M University, College Station, USA, (3) Department of Elementary Particles and Astrophysics, the Weizmann Institute of Science, Rehovot, Israel, (4) Institute for Nuclear Research, RAS, Moscow, Russia, (5) National Research Nuclear University ''MEPhI'', Moscow, Russia)

    The semimicroscopic particle-hole dispersive optical model (PHDOM) is implemented to describe main properties of Isoscalar Giant Multipole Resonances (up to L=3) in medium-heavy closed-shell nuclei. The main properties are characterized by the strength distribution, transition density, partial and total probabilities of direct one-nucleon decay. Calculation results obtained for the 208Pb nucleus are compared with available experimental data.

    Comments:
    33 pages, 6 tables, 8 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2011.03315 [pdf]
    PRC(2021)·9 citations
  3. 03

    [Submitted on 6 Nov 2020]

    Shear viscosity and electric conductivity of a hot and dense QGP with a chiral phase transition

    Olga Soloveva🇩🇪 · David Fuseau🇫🇷 · Jörg Aichelin🇫🇷 · Elena Bratkovskaya🇩🇪

    We calculate two transport coefficients -- the shear viscosity over entropy ratio and the ratio of the electric conductivity to the temperature -- of strongly interacting quark matter within the extended Polyakov Nambu-Jona-Lasinio (PNJL) model along the crossover transition line for moderate values of baryon chemical potential GeV as well as in the vicinity of the critical endpoint (CEP) and at large baryon chemical potential GeV, where the first-order phase transition takes place. The evaluation of the transport coefficients is performed on the basis of the effective Boltzmann equation in the relaxation time approximation. We employ two different methods for the calculation of the quark relaxation times: i) using the averaged transition rate defined via thermal averaged quark-quark and quark-antiquark PNJL cross sections and ii) using the 'weighted' thermal averaged quark-quark and quark-antiquark PNJL cross sections. The and transport coefficients have a similar temperature and chemical potential behavior when approaching the chiral phase transition for the both methods for the quark relaxation time, however, the differences grow with increasing temperature. We demonstrate the effect of the first-order phase transition and of the CEP on the transport coefficients in the deconfined QCD medium.

    Comments:
    16 pages, 21 figures, 4 tables
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2011.03505 [pdf]
    PRC(2021)·42 citations

Affiliations

first authorsco-authorsvia INSPIRE