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Nuclear Theory·nucl-th

Friday·March 7, 2025

7 papers—3 primary·4 cross-listed

All7Primary3Cross-lists4
  1. 01

    [Submitted on 6 Mar 2025]

    Quantum fluctuation energies over a spatially inhomogeneous field background in a chiral soliton model

    Jiarui Xia🇨🇳 · Song Shu🇨🇳 · Xiaogang Li🇨🇳

    Based on chiral soliton models, the quantum fluctuation energies of quarks over a spatially inhomogeneous meson field background have been thoroughly studied. We have used a systematic calculation scheme initiated by Schwinger, in which the loop quantum fluctuation energies are evaluated by a nontrivial level summation over the eigenvalue spectrum of the effective Hamiltonian of the system. The effective Hamiltonian can be constructed by one loop effective action of fluctuations of quarks over a static chiral soliton field background. The corresponding Dirac equation is obtained. In a static and spatially spherical case and by the hedgehog ansatz the radial part and the angular part of the grand spin of the wave function for the Dirac equation can be separated. Due to the soliton background the eigenvalue spectrum are distorted. The scattering phase shift can be determined by solve the radial equations at different momentum. The density of states in momentum space can be derived. The effective Hamiltonian has been diagonalized in a Hilbert space where the eigenfunctions are labeled by the parity, grand spin and energy. The renormalization scheme can be carried out by a Born subtraction of the phase shift and the compensating Feynman diagram renormalization. Finally the finite quantum fluctuation energies over chiral soliton background at different parities and grand spins have been numerically evaluated, compared and discussed.

    Comments:
    25 pages,9 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2503.04015 [pdf]
    PRC(2026)·0 citations
  2. 02

    [Submitted on 6 Mar 2025]

    Electroproduction of medium- and heavy-mass hypernuclei

    P. Bydžovský🇨🇿 · D. Denisova🇨🇿 · F. Knapp🇨🇿 · P. Veselý🇨🇿

    The DWIA formalism for computing the cross sections in electroproduction of hypernuclei used before for lighter (p-shell and sd-shell) systems is utilized in studying electroproduction on heavier targets such as Cr, and Pb. First, the effects from kaon distortion and kinematics are re-examined and then results for the heavy targets are discussed in view of various forms of the N effective interaction, the elementary amplitude, and kinematics. Apparent sensitivity of the hypernucleus excitation spectra to various forms of the N effective interaction is shown. Predictions of the excitation spectrum in electroproduction of Tl are also given in kinematics of the experiment E12-20-013 in preparation at Jefferson Lab.

    Comments:
    In the version v2, sections III and IV and Summary were revised, Fig.1 was omitted and new references added; more details on the formalism can be found in Phys. Rev. C 106, 044609 (2022) and ibid. 108, 024615 (2023)
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2503.04495 [pdf]
    PRC(2025)·2 citations
  3. 03

    [Submitted on 6 Mar 2025]

    Charge dependent directed flow splitting from baryon inhomogeneity and electromagnetic field

    Tribhuban Parida🇮🇳 · Sandeep Chatterjee🇮🇳 · Subhash Singha🇨🇳

    This work aims to understand the recent experimental data from the STAR collaboration on the system size dependence of directed flow splitting between oppositely charged hadrons [arXiv:2412.18326]. Previously, we have studied the role of baryon inhomogeneity on charge dependent directed flow. We now incorporate the effects of the electromagnetic (EM) field albeit perturbatively, as implemented in Ref. [arXiv:1806.05288]. This enables us to compare the relative contributions between baryon inhomogeneity and EM field on charge dependent directed flow. Our model calculation describes the experimental data on the centrality and system size dependence of the mid-rapidity directed flow slope splitting, , between protons and anti-protons. Our results indicate that in central collisions, where the EM field strength is negligible, the inclusion of EM field effects does not influence the splitting between protons and anti-protons. This suggests that the observed system size dependence of in central collisions arises solely from enhanced baryon stopping in larger collision systems. However, in semi-central and peripheral collisions, both baryon diffusion and EM field effects contribute to the splitting. Furthermore, the centrality dependence of is highly sensitive to the electrical conductivity of the medium, making it a potential probe for extracting this transport coefficient in the QCD medium through model-to-data comparisons. However, achieving this requires a precise determination of the background baseline originating from baryon diffusion. Additionally, further investigation is needed to understand for oppositely charged kaons and pions, particularly by incorporating the diffusion of other conserved charges.

    Comments:
    5 Figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2503.04660 [pdf]
    7 citations

Affiliations

first authorsco-authorsvia INSPIRE