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Nuclear Theory·nucl-th

Thursday·April 17, 2025

9 papers—3 primary·6 cross-listed

All9Primary3Cross-lists6
  1. 01

    [Submitted on 16 Apr 2025]

    Low-energy neutrino responses for 71Ga by electron capture rates, charge exchange reactions and shell model calculations

    Yoritaka Iwata🇯🇵 · Hiroyasu Ejiri🇯🇵 · Shahariar Sarkar🇮🇳

    Weak Gamow-Teller (GT) responses for low-lying states in are crucial for studying low-energy solar neutrinos and the Ga anomaly, i.e., the possible transition to the sterile state. The responses for the ground state, the first excited state, and the second excited state are evaluated for the first time using the experimental electron capture rates, the experimental charge exchange reaction (CER) rates corrected for the tensor-interaction effect and the theoretical interacting shell model (ISM) calculations. The contributions from the two excited states to the solar and neutrinos are found to be of that for the ground state. This is slightly larger than the ISM values but little smaller than the CER values without corrections for the tensor interaction effect. The Ga anomaly is far beyond the uncertainty of the obtained nuclear responses.

    Comments:
    submitted
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2504.11736 [pdf]
    PRC(2026)·0 citations
  2. 02

    [Submitted on 16 Apr 2025]

    Moment of inertia for pair rotation: Interplay between order parameter and shell structure

    Chisato Ruike · Nobuo Hinohara · Takashi Nakatsukasa

    [Background] Pair condensation in finite nuclei generates a collective motion known as pair rotation. The moment of inertia of pair rotation (P-MoI) has been used as an indicator of pair condensation. [Purpose] We aim to elucidate the fundamental properties of the P-MoI, particularly its dependence on the particle number and the order parameter. [Method] The P-MoI was evaluated using the Bardeen-Cooper-Schrieffer (BCS) calculations with a monopole pairing Hamiltonian and Skyrme density functional theory calculations with different density-dependent pairing energy density functionals. [Results] In open-shell nuclei, a negative correlation was found between the P-MoI and the pair amplitude, which is the order parameter for the transition from the normal phase to the superconducting phase. Analysis based on the decomposition of the P-MoI into the orbital contributions within the BCS approximation shows that its orbital dependence is very similar to that of the pairing gap. [Conclusions] The P-MoI reflects the influence of both the level density near the Fermi energy and the pair amplitude.

    Comments:
    12 pages, 8 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2504.11908 [pdf]
    0 citations
  3. 03

    [Submitted on 16 Apr 2025]

    Global polarization in heavy-ion collisions at high baryon density

    Yu. B. Ivanov🇷🇺

    Based on the model of three-fluid dynamics (3FD), the global polarization () is calculated in Au+Au collisions at 3 9 GeV, in which high baryon density is achieved. Various contributions to are considered: those from the thermal vorticity, meson field, thermal shear and spin-Hall effect. Feed-down from higher-lying resonances is also taken into account. The results are compared with available data. Special attention is payed to the collision energies of 3, 3.2, 3.5, 3.9, and 4.5 GeV, for which a thorough scan of the energy, rapidity, and centrality dependence of is performed. The results for 3 GeV reasonably well reproduce the corresponding STAR data. While the results at 3.2, 3.5, 3.9, and 4.5 GeV can be considered as predictions for results of measurements within the STAR fixed-target (STAR-FXT) programthat are expected in the nearest future. It is predicted that a broad maximum of is reached at 3--3.9 GeV, exact position of which depends on the centrality and width of the midrapidity range of observation. Impact of the meson-field, thermal-shear and spin-Hall-effect contributions to is also studied.

    Comments:
    12 pages, 12 figures, minor changes, version published in PRC
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2504.12200 [pdf]
    PRC(2025)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE