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Nuclear Theory·nucl-th

Friday·December 6, 2024

10 papers—5 primary·5 cross-listed

All10Primary5Cross-lists5
  1. 01

    [Submitted on 4 Dec 2024]

    Robustness of the proxy-SU(3) symmetry in atomic nuclei and the role of the next highest weight irreducible representation

    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, the collective deformation variables beta and gamma in even-even atomic nuclei away from closed shells based on the highest weight irreducible representations (irreps) of SU(3) in the relevant proton and neutron shells, which are the most symmetric irreps allowed by the Pauli principle and the short-range nature of the nucleon-nucleon interactions. The special cases in which the use of the next highest weight irrep of SU(3) becomes necessary are pointed out and numerical results are given for several regions of the nuclear chart, which can be used as input for irrep-mixing calculations.

    Comments:
    31 pages, 14 figures, 6 tables
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2412.03692 [pdf]
    Symmetry(2024)·7 citations
  2. 02

    [Submitted on 4 Dec 2024]

    A simple model to investigate jet quenching and correlated errors for centrality-dependent nuclear-modification factors in relativistic heavy-ion collisions

    Ron A Soltz🇺🇸 · Dhanush A Hangal🇺🇸 · Aaron Angerami🇺🇸

    We apply Bayesian techniques to compare a simple, empirical model for jet-quenching in heavy-ion collisions to centrality-dependent jet- measured by ATLAS for Pb+Pb collisions at ~TeV. We find that the values for central collisions are adequately described with a model for the mean -dependent jet energy-loss using only 2-parameters. This model is extended by incorporating 2D initial geometry information from TRENTO and compared to centrality-dependent values. We find that the results are sensitive to value of the jet-quenching formation time, , and that the optimal value of varies with the assumed path-length dependence of the energy-loss. We construct a covariance error matrix for the data from the dependent contributions to the ATLAS systematic errors and perform Bayesian calibrations for several different assumptions for the systematic error correlations. We show that most-probable functions and values are sensitive to assumptions made when fitting to correlated errors.

    Comments:
    13 pages, 16 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2412.03724 [pdf]
    PRC(2025)·7 citations
  3. 03

    [Submitted on 5 Dec 2024]

    Radial Oscillations in Hybrid Stars with Slow Quark Phase Transition

    Ishfaq Ahmad Rather🇩🇪 · Kauan D. Marquez🇵🇹 · Betânia C. Backes🇬🇧 · Grigoris Panotopoulos🇨🇱 · Ilídio Lopes🇵🇹

    This study investigates the radial oscillations of hybrid neutron stars, characterized by a composition of hadronic external layers and a quark matter core. Utilizing a density-dependent relativistic mean-field model that incorporates hyperons and baryons for describing hadronic matter, and a density-dependent quark model for quark matter, we analyze the ten lowest eigenfrequencies and their corresponding oscillation functions. Our focus lies on neutron stars with equations-of-state involving N, N + , N + H, and N + H + , featuring a phase transition to quark matter. Emphasizing the effects of a slow phase transition at the hadron-quark interface, we observe that the maximum mass is attained before the fundamental mode's frequency decreases for slow phase transitions. This observation implies the stability of stellar configurations with higher central densities than the maximum mass, called Slow Stable Hybrid Stars (SSHSs), even under small radial perturbations. The length of these SSHS branch depends upon the energy density jump between two phases and the stiffness of the quark EoS.

    Comments:
    Contribution for the conference proceedings of the "10th International Conference on Quarks and Nuclear Physics (QNP 2024)"
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
    arXiv:
    2412.04007 [pdf]
    PoS(2025)·0 citations
  4. 04

    [Submitted on 5 Dec 2024]

    Spin distribution of fission fragments involving bending and wriggling modes

    D.E. Lyubashevsky · A.A. Pisklyukov · Yu.D. Shcherbina · T.Yu. Shashkina · P.V. Kostryukov

    We present a closed analytical description of the spin distributions of the fragments produced in low-energy induced and spontaneous fission. In our model the high fragment spins and the relative orbital angular momentum arise from the zero-point transverse wriggling and bending oscillations of the two pre-fragments, under the postulate that the fissioning system remains ``cold'' up to scission -- its available energy being stored as non-equilibrium deformation rather than as heat. From the probability distributions of the two modes we derive a closed expression for the spin distribution of each fragment and for its mean value. The decisive quantities are the fragment moments of inertia, which we evaluate in the hydrodynamic model from the non-equilibrium scission deformations reconstructed from the measured prompt-neutron multiplicities. Confronted with the recent data on , , and , the model reproduces both the magnitude of the mean spins and their characteristic sawtooth dependence on the fragment mass. Comparison with the statistical and microscopic approaches indicates that the differences for individual fragments can be traced largely to the deformation dependence of the moments of inertia.

    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2412.04410 [pdf]
    Phys.Atom.Nucl.(2024)·3 citations
  5. 05

    [Submitted on 5 Dec 2024]

    Estimation of correlation coefficients and spin angular distributions of fission fragments

    D.E. Lyubashevsky · A.A. Pisklyukov · S.V. Klyuchnikov · P.V. Kostryukov

    This study proposes a theoretical model for studying the spin characteristics and angular correlations of fission fragments of heavy nuclei. The mechanisms of spin formation, including the influence of transverse vibrations, are considered and the relationship between the anisotropy of the angular distribution and the correlation coefficient is revealed. The theoretical predictions are compared with experimental data and various models developed by other research groups.

    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2412.04411 [pdf]
    PRC(2025)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE