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Nuclear Theory·nucl-th

Thursday·November 16, 2023

11 papers—6 primary·5 cross-listed

All11Primary6Cross-lists5
  1. 01

    [Submitted on 15 Nov 2023]

    Four-body bound states in momentum space: the Yakubovsky approach without two-body matrices

    M. Mohammadzadeh · M. Radin · K. Mohseni · M. R. Hadizadeh

    This study presents a solution to the Yakubovsky equations for four-body bound states in momentum space, bypassing the common use of two-body matrices. Typically, such solutions are dependent on the fully-off-shell two-body matrices, which are obtained from the Lippmann-Schwinger integral equation for two-body subsystem energies controlled by the second and third Jacobi momenta. Instead, we use a version of the Yakubovsky equations that doesn't require matrices, facilitating the direct use of two-body interactions. This approach streamlines the programming and reduces computational time. Numerically, we found that this direct approach to the Yakubovsky equations, using 2B interactions, produces four-body binding energy results consistent with those obtained from the conventional matrix dependent Yakubovsky equations, for both separable (Yamaguchi and Gaussian) and non-separable (Malfliet-Tjon) interactions.

    Subjects:
    Nuclear Theory (nucl-th); Computational Physics (physics.comp-ph); Quantum Physics (quant-ph)
    arXiv:
    2311.08713 [pdf]
    Front.in Phys.(2023)·3 citations
  2. 02

    [Submitted on 15 Nov 2023]

    Parameters of nucleon densities and the Coulomb barrier in heavy-ion collisions

    Makar Simonov (1 and 2 and 3) · Alexander Karpov (2 and 4) · Tatiana Tretyakova (2 and 3) ((1) II. Physikalisches Institut, Justus-Liebig-Universität Gießen, Gießen, Germany, (2) Joint Institute for Nuclear Research, Dubna, Russia, (3) Lomonosov Moscow State University, Moscow, Russia, (4) Dubna State University, Dubna, Russia)

    When modeling nuclear processes which occur in heavy-ion reactions, it is necessary to calculate the potential energy of interaction between two nuclei. One of the main features determining the dynamics of the nucleus-nucleus collision is the Coulomb barrier, the knowledge of which is especially important when low- and intermediate-energy reactions are being studied. Our goal is to establish a parameterization of nucleon density distributions for calculation of the nucleus-nucleus double-folding potential in nuclear reactions. Special attention is paid to the description of the Coulomb barrier. The study analyzes experimental data on charge radii, diffuseness, and neutron skin thickness of atomic nuclei. The nucleus-nucleus potential is calculated in the framework of the double-folding method with the effective nucleon-nucleon interaction taken in the form of the zero-range Migdal potential. Based on this analysis and comparison with the Bass potential, parameters of nucleon density distributions are fitted to reproduce the Coulomb barrier. A method for correcting the parameters of nucleon densities to reproduce the Coulomb barrier with the double-folding potential is proposed. The presented way to correct nucleon densities allows obtaining a satisfactory description of the Coulomb barrier that is important for modeling near-barrier collisions of heavy ions.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2311.08892 [pdf]
    0 citations
  3. 03

    [Submitted on 15 Nov 2023]

    Role of the isospin diffusion on cluster transfer in C + Bi reactions

    Zepeng Gao · Yinu Zhang · Long Zhu · Zehong Liao · Yu Yang · Chenchen Guo · Jun Su

    Heavy-ion collisions at near-barrier energies provide a crucial pathway for investigating nucleon correlations and clustering structures. Recent experimental results showed that the valence neutrons in light projectiles obviously enhance the transfer. This finding is extremely puzzled and fascinating, because it violates the ground-state value systematics unexpectedly. In this work, the time-dependent Hartree-Fock approach is utilized to investigate the cluster transfer. By comparing the reactions C + Bi, we discover that above puzzling behavior is because of the strong correlation between isospin diffusion and clustering. Our calculations clearly show that the equilibrium of neutron-to-proton ratio strongly inhibits the clustering. This work opens a prospect for investigating the clustering in open quantum system.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2311.08897 [pdf]
    PRC(2024)·5 citations
  4. 04

    [Submitted on 15 Nov 2023]

    Effective Range Approximation in Variable Phase Approach for Triplet and Singlet State

    Anil Khachi

    This work is a short communication where phase function method has been applied to obtain the phase shifts using Effective Range Approximation potential for , , , and states. No free fitting parameters are used in calculations and reasonably good match with the experimental phase shifts is observed for E 20 MeV. Potentials are obtained for n-n, n-p, and p-p scattering that are exponential well-shaped.

    Comments:
    9 pages, 5 figures. arXiv admin note: substantial text overlap with arXiv:2309.16780
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2311.08940 [pdf]
    Rom.J.Phys.(2025)·2 citations
  5. 05

    [Submitted on 15 Nov 2023]

    Constraints on Density Dependent MIT Bag Model Parameters for Quark and Hybrid Stars

    Soumen Podder🇮🇳 · Suman Pal🇮🇳 · Debashree Sen🇰🇷 · Gargi Chaudhuri🇮🇳

    We compute the equation of state (EoS) of strange quark stars (SQSs) with the MIT Bag model using density dependent bag pressure, characterized by a Gaussian distribution function. The bag pressure's density dependence is controlled by three key parameters namely the asymptotic value (), , and . We explore various parameter combinations (, , ) that adhere to the Bodmer-Witten conjecture, a criterion for the stability of SQSs. Our primary aim is to analyze the effects of these parameter variations on the structural properties of SQSs. However we find that none of the combinations can satisfy the NICER data for PSR J0030+0451 and the constraint on tidal deformability from GW170817. So it can be emphasized that this model cannot describe reasonable SQS configurations. We also extend our work to calculate structural properties of hybrid stars (HSs). With the density dependent bag model (DDBM), these astrophysical constraints are fulfilled by the HSs configurations within a very restricted range of the three parameters. The present work is the first to constrain the parameters of DDBM for both SQS and HSs using the recent astrophysical constraints on tidal deformabiity from GW170817 and that on mass-radius relationship from NICER data.

    Comments:
    Accepted for publication in Nuclear Physics A
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2311.08962 [pdf]
    NPA(2024)·26 citations
  6. 06

    [Submitted on 15 Nov 2023]

    Differential Rotation in Compact Objects with Hyperons and Delta Isobars

    Delaney Farrell🇺🇸 · Fridolin Weber🇺🇸 · Jia Jie Li🇨🇳 · Armen Sedrakian🇩🇪

    Neutron stars may experience differential rotation on short, dynamical timescales following extreme astrophysical events like binary neutron star mergers. In this work, the masses and radii of differentially rotating neutron star models are computed. We employ a set of equations of states for dense hypernuclear and -admixed-hypernuclear matter obtained within the framework of CDF theory in the relativistic Hartree-Fock (RHF) approximation. Results are shown for varying meson- couplings, or equivalently the -potential in nuclear matter. A comparison of our results with those obtained for non-rotating stars shows that the maximum mass difference between differentially rotating and static stars is independent of the underlying particle composition of the star. We further find that the decrease in the radii and increase in the maximum masses of stellar models when -isobars are added to hyperonuclear matter (as initially observed for static and uniformly rotating stars) persist also in the case of differentially rotating neutron stars.

    Comments:
    7 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    2311.09158 [pdf]
    Astron.Nachr.(2024)·0 citations

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first authorsco-authorsvia INSPIRE