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Nuclear Theory·nucl-th

Wednesday·October 30, 2024

15 papers—6 primary·9 cross-listed

All15Primary6Cross-lists9
  1. 01

    [Submitted on 28 Oct 2024]

    Comment on: "Investigating the time dependence of neutron-proton equilibration using molecular dynamics simulations" by A.Jedele et al: Phys Rev C 107, 024601 (2023)

    Massimo Papa (Istituto Nazionale Fisica Nucleare-Sezione di Catania, Catania, Italia)

    In this paper, the authors discuss neutron-proton equilibration process induced on the 70Zn + 70Zn system at 35 MeV/nucleon, comparing experimental results with the Anti-symmetrized Molecular Dynamics and the Constrained Molecular Dynamics model simulations (COMD). The comment contains observations on the improper use of the COMD model, including some misinterpretations of the obtained results.

    Comments:
    Comment on DOI 10.1103/PhysRevC.107.024601
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2410.21354 [pdf]
    0 citations
  2. 02

    [Submitted on 28 Oct 2024]

    Effective field theory for radiative corrections to charged-current processes II: Axial-vector coupling

    Vincenzo Cirigliano🇺🇸 · Wouter Dekens🇺🇸 · Emanuele Mereghetti🇺🇸 · Oleksandr Tomalak🇺🇸

    We discuss the hadronic structure-dependent radiative corrections to the axial-vector coupling that controls single-nucleon weak charged-current processes -- commonly denoted by . We match the Standard Model at the GeV scale onto chiral perturbation theory at next-to-leading order in the one-nucleon sector, in the presence of electromagnetic and weak interactions. As a result, we provide a representation for the corrections to in terms of infrared finite convolutions of simple kernels with the single-nucleon matrix elements of time-ordered products of two and three quark bilinears (vector, axial-vector, and pseudoscalar). We discuss strategies to determine the required non-perturbative input from data, lattice-QCD (+QED), and possibly hadronic models. This work paves the way for a precise comparison of the values of the ratio extracted from experiment and from lattice-QCD, which constrain physics beyond the Standard Model.

    Comments:
    53 pages, 3 figures, version published in Physical Review D, references added, minor changes in text
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2410.21404 [pdf]
    PRD(2025)·22 citations
  3. 03

    [Submitted on 29 Oct 2024]

    Microscopic optical potentials from a Greens function approach

    G. H. Sargsyan · G. Potel · K. Kravvaris · J. E. Escher

    Optical potentials are a standard tool in the study of nuclear reactions, as they describe the interaction between a target nucleus and a projectile. The use of phenomenological optical potentials built using experimental data on stable isotopes is widespread. Although successful in their dedicated domain, it is unclear whether these phenomenological potentials can provide reliable predictions for unstable isotopes. To address this problem, optical potentials based on microscopic nuclear structure input calculations prove to be crucial and are an important current line of research. In this work we present an explicit implementation of the Feshbach formalism for the systematic derivation of optical potentials using input from nuclear structure models. Numerical tools for the derivation of Green's functions associated with nonlocal potentials are presented. The new optical potential, based on the valence shell model, is applied to the calculations of n+24Mg elastic scattering and yields a close agreement with the experimental data.

    Comments:
    Accepted version
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2410.21714 [pdf]
    PRC(2025)·9 citations
  4. 04

    [Submitted on 29 Oct 2024]

    Probing nuclear liquid-gas phase transition with isospin correlations

    Michał Marczenko🇵🇱 · Krzysztof Redlich🇵🇱 · Chihiro Sasaki🇵🇱

    We investigate the fluctuations of the net-baryon number near the critical point of the liquid-gas phase transition. We use the parity doublet model in the mean-field approximation fixed to the zero-temperature properties of nuclear matter to account for critical behavior. We explicitly calculate the fluctuations of the net-proton and net-neutron numbers as well as their correlations in the isospin-symmetric matter. We focus on the qualitative properties and systematics of the first- to fourth-order susceptibilities and their ratios. We demonstrate that the fluctuations of net-proton number do not reflect the total net-baryon number fluctuations in the vicinity of the nuclear liquid-gas phase transition. We also study the behavior of the baryon and proton number factorial cumulants. We highlight the importance of the non-trivial correlations between protons and neutrons.

    Comments:
    Section on factorial cumulants added; matches publised version
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2410.21746 [pdf]
    PRC(2025)·7 citations
  5. 05

    [Submitted on 29 Oct 2024]

    Volume fluctuations affect on transport and thermodynamic coefficients in p-Pb systems

    De-Xian Wei🇨🇳

    We use A Multi-Phase Transport (AMPT) model to simulate the event-by-event p-Pb collisions at =5.02 TeV. To study the space-time volume fluctuations, two different definitions of radius have been introduced in the calculation: One is weigh of event-by-event charged multiplicity (noted as set I), and the other one is weigh of energy density in a single event (notes as set II). Based on calculations of sets I and II, the transport and thermodynamic coefficients, such as the speed of sound squared, shear viscosity, bulk viscosity, and mean free path are both dependent on the radius and local temperature. By comparing results of sets I and II, we found that these transport and thermodynamic coefficients differed significantly in the results. These results imply that the transport and thermodynamic properties of the medium in small collisions significantly depend on the space-time volume fluctuations.

    Comments:
    7 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2410.21902 [pdf]
    0 citations
  6. 06

    [Submitted on 29 Oct 2024]

    A Gaussian Process Generative Model for QCD Equation of State

    Jiaxuan Gong🇺🇸 · Hendrik Roch🇺🇸 · Chun Shen🇺🇸

    We develop a generative model for the nuclear matter equation of state at zero net baryon density using the Gaussian Process Regression method. We impose first-principles theoretical constraints from lattice QCD and hadron resonance gas at high- and low-temperature regions, respectively. By allowing the trained Gaussian Process Regression model to vary freely near the phase transition region, we generate random smooth cross-over equations of state with different speeds of sound that do not rely on specific parameterizations. We explore a collection of experimental observable dependencies on the generated equations of state, which paves the groundwork for future Bayesian inference studies to use experimental measurements from relativistic heavy-ion collisions to constrain the nuclear matter equation of state.

    Comments:
    12 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2410.22160 [pdf]
    PRC(2025)·11 citations

Affiliations

first authorsco-authorsvia INSPIRE