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Nuclear Theory·nucl-th

Friday·December 13, 2024

12 papers—6 primary·6 cross-listed

All12Primary6Cross-lists6
  1. 01

    [Submitted on 11 Dec 2024]

    Thermomagnetic Effects of Quark Matter in the NJL Model: Application of Regularization Schemes

    Xiang-Qiong Liu🇨🇳

    In the SU(3) Nambu-Jona-Lasinio (NJL) model of a thermally magnetized medium, the regularization methods adopted for the thermodynamic potential and the mass gap equation are utilized to calculate the relevant thermodynamic quantities in thermomagnetic quark matter. When dealing with the thermodynamic quantities and the gap equation, three schemes can be chosen, namely magnetic field-independent regularization, soft cut-off regularization, and Pauli-Villars regularization. These three regularization schemes have different influences on the properties of thermomagnetic quark matter, and different choices of regularization schemes will also lead to different effects in the calculation of the properties of thermomagnetic quark matter.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2412.08674 [pdf]
    0 citations
  2. 02

    [Submitted on 11 Dec 2024]

    Bayesian evidence for two peaks in the sound speed in cold dense QCD

    Dake Zhou🇺🇸

    I show that in addition to the well-known peak inside massive neutron stars, the sound speed in cold dense QCD matter likely exhibits another peak above neutron star densities before it asymptotes to . Based on the framework reported in arxiv:2408.16738, this approach does not rely on any assumption about the ultra-dense matter not realized in nature. Current multimessenger observation of neutron stars favors the two-peak scenario with a Bayes factor , where the uncertainties are systematics due to models of neutron star inner cores. This evidence grows to if the component of GW190814 is a neutron star. The trough in separating the two peaks is inferred to be below (at the level) if neutron stars exist. The second peak above beyond baryon chemical potential GeV most likely signals non-perturbative effects in cold quark matter, for instance color superconductivity.

    Comments:
    clarify simplifications made in the reasoning in main text; the proof in appendix is robust. comments are welcome
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
    arXiv:
    2412.08760 [pdf]
    2 citations
  3. 03

    [Submitted on 11 Dec 2024]

    Scattering phase shifts from overlap relations in the -matrix method

    Calvin W. Johnson · Bui Minh Loc · Austin Keller · Kenneth M. Nollett

    The scattering problem can be implemented in a square-integrable basis via the so-called -matrix method. While methods to compute the phase shift in the -matrix approach are known, we introduce a novel formula in square-integrable bases analogous to existing integral relations or overlap integrals in a (continuous) position basis. We demonstrate the method in single-channel potential scattering. Such a result is the first step towards a more general approach to scattering and reactions in popular many-body methods such as the configuration-interaction shell model.

    Comments:
    13 pages, 4 figures; minor update to author list; minor edits to abstract
    Subjects:
    Nuclear Theory (nucl-th); Atomic Physics (physics.atom-ph)
    arXiv:
    2412.08825 [pdf]
    PRC(2026)·0 citations
  4. 04

    [Submitted on 12 Dec 2024]

    Exploring nuclear force with pulsar glitch observation

    Zhong-Hao Tu · Ang Li

    We connect nuclear forces to one of the most notable irregular behaviors observed in pulsars, already detected in approximately 6\% known pulsars, with increasingly accurate data expected from upcoming high-precision timing instruments on both ground and space. Built on Shang & Li (2021), we conduct a case study on the 2001 glitch of the Vela pulsar. For our purpose, we adopt the Relativistic Mean Field (RMF) model as the theoretical many-body framework to describe nuclear systems. We refit three representative RMF parameter sets (DD-ME2, PKDD, NL3), considering the uncertainties in nuclear matter saturation properties. Utilizing the resulting star structure, composition and nucleon properties in the medium obtained in a consistent manner, we calculate the pinning energy of superfluid vortex in the nuclear lattice in the inner crust. This leads to the evolution of associated pinning force that acts on the vortex, which can be confronted with observed glitch amplitude and short-time relaxation in the 2000 Vela glitch event, following the snowplow model of pulsar glitch. We discuss how the vortex configuration and pinning properties depend on the nuclear parameters, and find an interesting and dominant role of the nuclear symmetry energy slope on pinning strength.

    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
    arXiv:
    2412.09219 [pdf]
    ApJ(2025)·8 citations
  5. 05

    [Submitted on 12 Dec 2024]

    Extended Skyrme effective interactions with higher-order momentum-dependence for transport models and neutron stars

    Si-Pei Wang🇨🇳 · Xin Li🇨🇳 · Rui Wang🇮🇹 · Jun-Ting Ye🇨🇳 · Lie-Wen Chen🇨🇳

    The recently developed extended Skyrme effective interaction based on the so-called N3LO Skyrme pseudopotential is generalized to the general NLO case by incorporating the derivative terms up to 2th-order into the central term of the pseudopotential. The corresponding expressions of Hamiltonian density and single-nucleon potential are derived within the Hartree-Fock approximation under general nonequilibrium conditions. The inclusion of the higher-order derivative terms provides additional higher-order momentum dependence for the single-nucleon potential, and in particular, we find that the N5LO single-nucleon potential with momentum dependent terms up to can give a nice description for the empirical nucleon optical potential up to energy of GeV. At the same time, the density-dependent terms in the extended Skyrme effective interaction are extended correspondingly in the spirit of the Fermi momentum expansion, which allows highly flexible variation of density behavior for both the symmetric nuclear matter equation of state and the symmetry energy. Based on the Skyrme pseudopotential up to N3LO, N4LO and N5LO, we construct a series of interactions with the nucleon optical potential having different high-momentum behaviors and with the symmetry potentials featuring different linear isospin-splitting coefficients for nucleon effective mass, by which we study the properties of nuclear matter and neutron stars. Furthermore, within the lattice BUU transport model, some benchmark simulations with selected interactions are performed for the Au+Au collisions at a beam energy of GeV/nucleon, and the predicted collective flows for protons are found to nicely agree with the data measured by HADES collaboration.

    Comments:
    36 pages, 13 figures, 9 tables. LBUU simulations for Au+Au@HADES updated and discussions added. Accepted version to appear in PRC. arXiv admin note: text overlap with arXiv:2312.17105
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2412.09393 [pdf]
    PRC(2025)·13 citations
  6. 06

    [Submitted on 12 Dec 2024]

    High Precision Binding Energies from Physics Informed Machine Learning

    Ian Bentley · James Tedder · Marwan Gebran · Ayan Paul

    Twelve physics-informed machine learning models have been trained to model binding energy residuals. Our approach begins with determining the difference between measured experimental binding energies and three different mass models. Then four machine learning approaches are used to train on each energy difference. The most successful ML technique, both in interpolation and extrapolation, is the least squares boosted ensemble of trees. The best model resulting from that technique utilizes eight physical features to model the difference between experimental atomic binding energy values in AME 2012 and the Duflo Zuker mass model. This resulted in a model that fit the training data with a standard deviation of 17 keV and that has a standard deviation of 92 keV when compared all of the values in the AME 2020. The extrapolation capability of each model is discussed, and the accuracy of predicting new mass measurements has also been tested.

    Comments:
    Version 2 contains edits including those based on referee feedback
    Subjects:
    Nuclear Theory (nucl-th); Computational Physics (physics.comp-ph)
    arXiv:
    2412.09504 [pdf]
    PRC(2025)·12 citations

Affiliations

first authorsco-authorsvia INSPIRE