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Nuclear Theory·nucl-th

Thursday·November 11, 2021

7 papers—3 primary·4 cross-listed

All7Primary3Cross-lists4
  1. 01

    [Submitted on 9 Nov 2021]

    How perturbative QCD constrains the Equation of State at Neutron-Star densities

    Oleg Komoltsev🇳🇴 · Aleksi Kurkela🇳🇴

    We demonstrate in a general and analytic way how high-density information about the equation of state (EoS) of strongly interacting matter obtained using perturbative Quantum Chromodynamics (pQCD) constrains the same EoS at densities reachable in physical neutron stars. Our approach is based on utilizing the full information of the thermodynamic potentials at the high-density limit together with thermodynamic stability and causality. This requires considering the pressure as a function of chemical potential instead of the commonly used pressure as a function of energy density . The results can be used to propagate the pQCD calculations reliable around 40 to lower densities in the most conservative way possible. We constrain the EoS starting from only few times the nuclear saturation density and at we exclude at least 65% of otherwise allowed area in the -plane. This provides information complementary to astrophysical observations that should be taken into account in any complete statistical inference study of the EoS. These purely theoretical results are independent of astrophysical neutron-star input, and hence, they can also be used to test theories of modified gravity and BSM physics in neutron stars.

    Comments:
    v2: the version published in PRL. A comparison of publicly available EoSs with new constraints added to the appendix C
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2111.05350 [pdf]
    PRL(2022)·234 citations
  2. 02

    [Submitted on 10 Nov 2021]

    Calculations of the alpha decay half-lives of some Polonium isotopes using the double folding model

    W. A. Yahya · K. J. Oyewumi

    The calculations of the alpha decay half-lives of some Polonium isotopes in the mass range 186 - 218 have been carried out using the Wentzel-Kramers-Brillouin (WKB) semiclassical approximation. The alpha-nucleus effective potential used contains the Coulomb potential, centrifugal potential, and the nuclear potential. The nuclear potential is obtained via the double folding model, with the microscopic NN effective interactions derived from relativistic mean field theory Lagrangian (termed R3Y). Different parametrizations of the R3Y interactions have been employed in the computation of the nuclear potentials. The results obtained using the R3Y NN interactions are compared with the ones obtained using the famous Michigan-3-Yukawa (M3Y) interactions. The use of density-dependent NN interaction is also considered. When compared to available experimental data, there are improvements in the results when density-dependent interaction potentials are used compared to when density-independent interactions are employed.

    Comments:
    17 pages
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2111.05604 [pdf]
    Acta Phys.Polon.B(2021)·7 citations
  3. 03

    [Submitted on 10 Nov 2021]

    Density dependence of symmetry energy and neutron skin thickness revisited using relativistic mean field models with nonlinear couplings

    Chiranjib Mondal🇫🇷

    The correlation between neutron skin-thickness of a neutron-rich nucleus and slope parameter of symmetry energy is assessed as a function of density using relativistic mean field models containing non-linear couplings among different mesons. Models with larger skin were found to probe the slope parameter even at suprasaturation densities, whereas models with smaller skin were observed to be sensitive only at specific subsaturation density, connected to the average density of nuclei. Possible reasons behind this density dependence are explored systematically. These results might be model specific, which need to be reassessed in other type of interactions existing in the literature. Nevertheless, extrapolating the predictions at high densities from models, which are optimized by data at saturation or subsaturation densities, needs to be handled with care.

    Comments:
    6 figures, 7 pages
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Experiment (nucl-ex)
    arXiv:
    2111.05743 [pdf]
    PRC(2022)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE