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Nuclear Theory·nucl-th

Monday·November 20, 2017

5 papers—2 primary·3 cross-listed

All5Primary2Cross-lists3
  1. 01

    [Submitted on 17 Nov 2017]

    Partial restoration of chiral symmetry in cold nuclear matter: the -meson case

    J.J. Cobos-Martínez🇲🇽 · K Tsushima🇧🇷 · G Krein🇧🇷 · A W Thomas🇦🇺

    The work presented at this workshop is divided into two parts. In the first part, the mass and decay width of the -meson in cold nuclear matter are computed in an effective Lagrangian approach. The medium dependence of these properties are obtained by evaluating kaon-antikaon loop contributions to the -meson self-energy, employing medium-modified kaon masses calculated using the quark-meson coupling model. The loop integral is regularized with a dipole form factor, and the sensitivity of the results to the choice of cutoff mass in the form factor is investigated. At normal nuclear matter density, we find a downward shift of the mass by a few percent, while the decay width is enhanced by an order of magnitude. Our results support the literature which suggest that one should observe a small downward mass shift and a large broadening of the decay width. In the second part, we present -meson--nucleus bound state energies and absorption widths for four selected nuclei, calculated by solving the Klein-Gordon equation with complex optical potentials. The attractive potential for the -meson in the nuclear medium originates from the in-medium enhanced KK loop in the -meson selfenergy. The results suggest that the -meson should form bound states with all the nuclei considered. However, the identification of the signal for these predicted bound states will need careful investigation because of their sizable absorption widths.

    Comments:
    Proceedings of the XXXI Annual Meeting of the Division of Particles and Fields of the Mexican Physical Society
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1711.06358 [pdf]
    J.Phys.Conf.Ser.(2017)·5 citations
  2. 02

    [Submitted on 17 Nov 2017]

    Neutron skins and neutron stars in the multi-messenger era

    F. J. Fattoyev · J. Piekarewicz · C. J. Horowitz

    The historical first detection of a binary neutron star merger by the LIGO-Virgo collaboration [B. P. Abbott et al. Phys. Rev. Lett. 119, 161101 (2017)] is providing fundamental new insights into the astrophysical site for the -process and on the nature of dense matter. A set of realistic models of the equation of state (EOS) that yield an accurate description of the properties of finite nuclei, support neutron stars of two solar masses, and provide a Lorentz covariant extrapolation to dense matter are used to confront its predictions against tidal polarizabilities extracted from the gravitational-wave data. Given the sensitivity of the gravitational-wave signal to the underlying EOS, limits on the tidal polarizability inferred from the observation translate into constraints on the neutron-star radius. Based on these constraints, models that predict a stiff symmetry energy, and thus large stellar radii, can be ruled out. Indeed, we deduce an upper limit on the radius of a neutron star of . Given the sensitivity of the neutron-skin thickness of Pb to the symmetry energy, albeit at a lower density, we infer a corresponding upper limit of about . However, if the upcoming PREX-II experiment measures a significantly thicker skin, this may be evidence of a softening of the symmetry energy at high densities---likely indicative of a phase transition in the interior of neutron stars.

    Comments:
    6 pages, 4 figures, edited figures and the text with a more correct interpretation of the LIGO-Virgo results
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Experiment (nucl-ex)
    arXiv:
    1711.06615 [pdf]
    PRL(2018)·476 citations

Affiliations

first authorsco-authorsvia INSPIRE