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Nuclear Theory·nucl-th

Monday·June 27, 2022

7 papers—4 primary·3 cross-listed

All7Primary4Cross-lists3
  1. 05

    [Submitted on 24 Jun 2022] (cross-list from gr-qc)

    Configurational entropy as a probe of the stability condition of compact objects

    P.S. Koliogiannis🇬🇷 · G.A. Tsalis🇬🇷 · C.P. Panos🇬🇷 · Ch.C. Moustakidis🇬🇷

    We systematically extend the statement that the configurational entropy provides an alternative approach to studying gravitational stability of compact objects, carried out in the previous work of M. Gleiser and N. Jiang, Phys. Rev. D {\bf 92}, 044046 (2015). Inspired by that paper, we try to answer the crucial question: Is there any one-to-one correspondence between the minimum of the configurational entropy and the stability point for each realistic equation of state? In view of the above question, we focus on neutron stars, quark stars, as well as on the third family of compact stars (hybrid stars), where a possible phase transition may lead to the existence of twin stars (stars with equal mass but different radius). In each case, we use a large set of equations of state investigating the possibility to find correlations between the stability region obtained from the traditional perturbation methods to the one obtained by the minimum of configurational entropy. We found that the suggested prediction of the stability by the minimization of the configurational entropy, concerning neutron stars and quark stars, does not have, at least quantitatively, universal validity. However, in several cases it qualitatively predicts the existence of the stability point. In conclusion, the configurational entropy, can be considered as an additional tool which enters into the quiver for studying the stability of compact objects such as for example neutron and quark stars, but taking into account that the accuracy of the predictions depends on the specific character of each equation of state.

    Comments:
    v1: 9 pages, 3 figures; v2: 5 pages, 4 figures; accepted for publication in Physical Review D
    Subjects:
    General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th); Computational Physics (physics.comp-ph)
    arXiv:
    2206.12138 [pdf]
    PRD(2023)·10 citations
  2. 06

    [Submitted on 24 Jun 2022] (cross-list from nucl-ex)

    Analysis of one-neutron transfer reaction in O + Se collision at 275 MeV

    I. Ciraldo🇮🇹 · F. Cappuzzello🇮🇹 · M. Cavallaro🇮🇹 · D. Carbone🇮🇹 · S. Burrello🇩🇪 · A. Spatafora🇮🇹 · A. Gargano🇮🇹 · G. De Gregorio🇮🇹 · R. I. Magaña Vsevolodovna🇮🇹 · L. Acosta🇲🇽 · C. Agodi🇮🇹 · P. Amador-Valenzuela🇧🇷 and 36 other authors

    Purpose: We want to analyze transitions to low-lying excited states of the residual and ejectile nuclei in the 76Se(18O, 17O) 77Se one-neutron stripping reaction at 275-MeV incident energy and determine the role of single-particle and core excitation in the description of the measured cross sections. In addition, we explore the sensitivity of the calculated cross section to different nuclear structure models. Methods: The excitation energy spectrum and the differential cross-section angular distributions are measured using the MAGNEX large acceptance magnetic spectrometer for the detection of the ejectiles and the missing mass technique for the reconstruction of the reaction kinematics. The data are compared with calculations based on distorted-wave Born approximation, coupled-channels Born approximation, and coupled reaction channels adopting spectroscopic amplitudes for the projectile and target overlaps derived by large-scale shell-model calculations and interacting boson-fermion model. Results: Peaks in the energy spectra corresponding to groups of unresolved transitions to 77Se and 17O are identified. The experimental cross sections are extracted and compared to theoretical calculations. A remarkable agreement is found, without using any scaling factors, demonstrating that the adopted models for nuclear structure and reaction take into account the relevant aspects of the studied processes. The main transitions which contribute to the cross section of each peak are identified.

    Comments:
    15 pages, 4 figures
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2206.12341 [pdf]
    PRC(2022)·34 citations
  3. 07

    [Submitted on 24 Jun 2022] (cross-list from hep-ph)

    Thermalization of gluons in spatially homogeneous systems

    Sergio Barrera Cabodevila🇪🇸 · Carlos A. Salgado🇪🇸 · Bin Wu🇪🇸

    We investigate thermalization of gluons in spatially homogeneous systems using the Boltzmann equation in diffusion approximation. A complete picture on thermalization is obtained for both initially under- and over-populated systems. In an initially under-populated system, we find that its soft sector undergoes three stages: overheating, cooling/overcooling and reheating before full thermalization is achieved. In an initially over-populated system, we find that its soft sector only undergoes two stages towards full thermalization: overheating and cooling. The cooling stage is consistently driven by momentum broadening due to multiple elastic collisions, manifest as a non-thermal scaling solution.

    Comments:
    10 pages, 3 figures, minor changes, version to appear in PLB
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2206.12376 [pdf]
    PLB(2022)·14 citations

Affiliations

first authorsco-authorsvia INSPIRE