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Nuclear Theory·nucl-th

Monday·December 9, 2024

10 papers—3 primary·7 cross-listed

All10Primary3Cross-lists7
  1. 01

    [Submitted on 5 Dec 2024]

    Ab initio calculations of overlap integrals for conversion in nuclei

    Matthias Heinz🇩🇪 · Martin Hoferichter🇨🇭 · Takayuki Miyagi🇯🇵 · Frederic Noël🇨🇭 · Achim Schwenk🇩🇪

    The rate for conversion in nuclei is set to provide the most stringent test of lepton-flavor symmetry and a window into physics beyond the Standard Model. However, to disentangle new lepton-flavor-violating interactions, in combination with information from and , it is critical that uncertainties at each step of the analysis be controlled and fully quantified. In this regard, nuclear response functions related to the coupling to neutrons are notoriously problematic, since they are not directly constrained by experiment. We address these shortcomings by combining ab initio calculations with a recently improved determination of charge distributions from electron scattering by exploiting strong correlations among charge, point-proton, and point-neutron radii and densities. We present overlap integrals for Al, Ca, and Ti including full covariance matrices, allowing, for the first time, for a comprehensive consideration of nuclear structure uncertainties in the interpretation of experiments.

    Comments:
    13 pages, 10 figures, 5 tables
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2412.04545 [pdf]
    PLB(2025)·16 citations
  2. 02

    [Submitted on 6 Dec 2024]

    Impact of the Scalar Isovector -meson on the description of nuclear matter and neutron star properties

    Lavínia Gabriela Teodoro dos Santos🇵🇹 · Tuhin Malik🇵🇹 · Constança Providência🇵🇹

    The implications of including the scalar isovector -meson in a relativistic mean-field description of nuclear matter are discussed. A Bayesian inference approach is used to determine the parameters that define the isovector properties of the model. The properties of nuclear matter and neutron stars are discussed. The inclusion of the -meson has only a small effect on the maximum mass of the neutron star (NS) and on the speed of sound in its interior, but it has a strong effect on the radius and the tidal deformability of low and medium mass stars. This is mainly due to the effect of the -meson on the symmetry energy and its slope and curvature at saturation, increasing the range of possible values of these three properties, and in particular allowing positive values of the symmetry energy curvature. Due to the effect of the -meson on the symmetry energy, the proton content of the star is also strongly affected. The inclusion of the -meson in the relativistic mean-field description of nuclear matter extends the phase space spanned by the model, allowing for a more flexible density dependence of the symmetry energy compatible with experimental, observational, and ab initio constraints.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2412.04946 [pdf]
    PRC(2025)·9 citations
  3. 03

    [Submitted on 6 Dec 2024]

    Excited cluster states: A new source for proton number fluctuations in the high baryon density regime

    Boris Tomasik🇸🇰 · Marcus Bleicher🇩🇪

    We calculate the contribution of the decay products of excited nuclear cluster states to the event-by-event fluctuations of protons in the energy range from ~GeV within the statistical model. We find that the inclusion of the excited nuclear clusters yields corrections to all cumulant ratios, ranging from 1\% for ratio of second to first-order cumulant to 100\% for the sixth to second order cumulant towards the lowest inspected energy. As expected the contribution of excited cluster states is most important at low energies ~GeV and becomes negligible at higher collision energies. Especially in light of the expected ultra-high precision data from CBM at FAIR, this new contribution is important to allow for a quantitative comparison with (potentially later available) lattice QCD or effective model results.

    Comments:
    5 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2412.04994 [pdf]
    PLB(2025)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE