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Nuclear Theory·nucl-th

Wednesday·November 20, 2024

14 papers—5 primary·9 cross-listed

All14Primary5Cross-lists9
  1. 01

    [Submitted on 18 Nov 2024]

    Quantum van der Waals quarkyonic matter at non-zero isospin asymmetry

    Tripp Moss🇺🇸 · Roman Poberezhniuk🇺🇸 · Volodymyr Vovchenko🇺🇸

    We extend the recently developed quantum van der Waals quarkyonic matter to non-zero isospin asymmetries by utilizing the two-component van der Waals equation with a generalized excluded volume prescription. The isospin dependence of van der Waals interaction parameters is determined by constraints on the symmetry energy, slope of the symmetry energy, and nuclear ground state properties. We find that the speed of sound has a peak for all values of the asymmetry parameter, signifying a transition to quarkyonic matter. The quarkyonic matter onset density is found to have a mild dependence on isospin asymmetry, with specific details influenced by the isospin dependence of the repulsive interactions. We also incorporate leptonic degrees of freedom and explore the neutron star matter equation of state, calculating mass-radius relations and tidal properties of neutron stars. We find that quarkyonic matter supports heavy neutron stars with a maximum mass of at least 2.6 solar masses. We observe quantitatively different behavior for the excluded volume cases of isospin-blind () and isospin-dependent () repulsion, the latter being preferred by observational constraints.

    Comments:
    10 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2411.11996 [pdf]
    PRC(2025)·8 citations
  2. 02

    [Submitted on 19 Nov 2024]

    Charmonia Production in Hot QCD Matter and Electromagnetic Fields

    Shuhan Zheng🇨🇳 · Jiamin Liu🇨🇳 · Shiqi Zheng🇺🇸 · Jiaxing Zhao🇩🇪 · Baoyi Chen🇨🇳

    Both hot QCD matter and extremely strong electromagnetic fields are generated in relativistic heavy-ion collisions. We employ the transport model and the equivalent photon approximation (EPA) to study charmonium hadroproduction and photoproduction in nucleus-nucleus collisions, respectively. In photoproduction, quasi-real photons may interact with the whole nucleus or individual nucleons, which is called the coherent and incoherent processes, respectively. The typical momentum of charmonium produced in two processes is located in and , where and are the radii of nucleus and the nucleon. Both kinds of photoproduction and also hadroproduction are considered to calculate charmonium production in different transverse momentum bins, rapidity bins, and collision centralities, incorporating modifications from hot QCD matter and initial cold nuclear matter effects. Our calculations explain experimental data about charmonium nuclear modification factors and the production cross-section in ultra-peripheral collisions. Charmonium nuclear modification is far above the unit at extremely low ( GeV/c) in peripheral collisions with centrality 70-90\%, attributed to coherent photoproduction.

    Comments:
    9 pages, 12 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2411.12169 [pdf]
    PRC(2025)·3 citations
  3. 03

    [Submitted on 19 Nov 2024]

    Exclusive photo-production on nuclei

    Sang-Ho Kim🇰🇷 · T.-S. H. Lee🇺🇸 · R.B. Wiringa🇺🇸

    Motivated by the recent experimental developments, the Pom-CQM model of the reaction of Lee et al. [Eur. Phys. J. A. 58, 252 (2022)] and Sakinah et al. [Phys. Rev. C. 109, 065204 (2024)] has been applied to predict the exclusive photo-production on nuclei (). Within the multiple scattering theory, the calculations have been performed by including the impulse amplitude and the -nucleus final state interaction (FSI) amplitude . For the deuteron target, is calculated exactly using the wave function generated from the realistic nucleon-nucleon potentials. It is found that, near the threshold region, the photo-production cross sections depend sensitively on the -state of the deuteron wave function. The FSI amplitude is calculated using the first-order optical potential constructed from the - scattering amplitude generated from the employed Pom-CQM model. It turns out that the FSI has significant effects in the large momentum-transfer region. By using the conventional fixed scatter approximation (FSA) and the nuclear form factors from the variational Monte-Carlo (VMC) calculations of Lonardoni et al. [Phys. Rev.C. 96, 024326 (2017)], the cross sections of the photo-production on , , and are also predicted for future experimental investigations at JLab and EIC.

    Comments:
    15 pages, 16 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2411.12187 [pdf]
    PRC(2025)·2 citations
  4. 04

    [Submitted on 19 Nov 2024]

    Preponderance of triaxial shapes in atomic nuclei predicted by the proxy-SU(3) symmetry

    Dennis Bonatsos · Andriana Martinou · S.K. Peroulis · D. Petrellis · P. Vasileiou · T.J. Mertzimekis · N. Minkov

    The proxy-SU(3) symmetry predicts, in a parameter-free way, based only on the Pauli principle and the short-range nature of the nucleon-nucleon interaction, non-vanishing values of the collective variable gamma almost everywhere across the nuclear chart. Substantial triaxiality with gamma between 15 and 45 degrees is proved to be expected along horizontal and vertical stripes on the nuclear chart, covering the nucleon numbers 22-26, 34-48, 74-80, 116-124, 172-182. Empirical support for these stripes is found by collecting all even-even nuclei for which the first two excited 2+ states are known, along with the B(E2)s connecting them, as well as the second 2+ state to the ground state. The stripes are related to regions in which oblate SU(3) irreducible representations appear, bearing similarity to the appearance of triaxiality within the SU(3)* dynamical symmetry of the interacting boson model-2. Detailed comparisons of the proxy-SU(3) predictions to the data and to predictions by state-of-the-art Monte Carlo shell model calculations for deformed N=94, 96, 98 isotones in the rare earth region show good overall agreement, with the exception of Z=70 and N=94, which correspond to fully symmetric proxy-SU(3) irreps, suggesting that the latter are an artifact of the method which can be amended by considering the influence of the neighboring irreps.

    Comments:
    16 pages, 6 figures, 3 tables
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2411.12281 [pdf]
    J.Phys.G(2025)·12 citations
  5. 05

    [Submitted on 19 Nov 2024]

    Nuclear Pairing Energy vs Mean Field Energy: Do They Talk To Each Other For Searching The Energy Minimum?

    Myeong-Hwan Mun · Eunja Ha · Myung-Ki Cheoun · Yusuke Tanimura · Hiroyuki Sagawa · Gianluca Colò

    We study the evolution of the total binding energy (TBE) and pairing energy of Pb, Hg and Ar isotopes, as a function of the nuclear deformation. As for the nuclear model, we exploit a deformed relativistic Hartree-Bogoliubov theory in the continuum (DRHBc), and a deformed Skyrme Hartree-Fock plus BCS model. It is found that the dependence of pairing energy on the deformation is strongly correlated to that of the mean field energy, which is obtained by subtracting the pairing energy from the TBE; in other words, the energy minimum characterized by a large negative mean field energy has a smaller negative pairing energy or, equivalently, a smaller positive pairing gap, while a stronger pairing energy is found in the region away from the minimum of the total energy. Consequently, the two energies show an anti-symmetric feature in their deformation dependence, although the energy scales are very different. Moreover, since the pairing energy has a negative sign with respect to to the pairing gap, the evolution of mean field energy follows closely that of the pairing gap. This implies that the pairing energy (or pairing gap) and the mean field energy talk to each other and work together along the potential energy curve to determine the energy minimum and/or the local minimum.

    Comments:
    20 pages, 8 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2411.12282 [pdf]
    PRC(2025)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE