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Nuclear Theory·nucl-th

Wednesday·July 28, 2021

5 papers—3 primary·2 cross-listed

All5Primary3Cross-lists2
  1. 01

    [Submitted on 27 Jul 2021]

    Fixed point behavior of cumulants in the three-dimensional Ising universality class

    Xue Pan🇨🇳

    High-order cumulants and factorial cumulants of conserved charges are suggested to study the critical dynamics in heavy-ion collision experiments. In this paper, using the parametric representation of the three-dimensional Ising model which is believed to belong to the same universality class with the Quantum chromo-dynamics, temperature dependence of the second- to fourth-order (factorial) cumulants of the order parameter is studied. It is found that the values of the normalized cumulants are independent of the external magnetic field at the critical temperature, which results in a fixed point in the temperature dependence of the normalized cumulants. In finite-size systems simulated by Monte Carlo method, the fixed point behavior still exists at the temperature near the critical one. The fixed point behavior is also appeared in the temperature dependence of normalized factorial cumulants at least from the fourth-order one. With a mapping from the Ising model to QCD, the fixed point behavior is also found in the energy dependence of the normalized cumulants (or fourth-order factorial cumulants) along different freeze-out curves.

    Comments:
    10 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2107.12758 [pdf]
    CPC(2022)·2 citations
  2. 02

    [Submitted on 27 Jul 2021]

    Weisskopf units for neutron-proton pair transfers

    J. A. Lay · Y. Ayyad · A. O. Macchiavelli

    We introduce the concept of neutron-proton two-particle units (-Weisskopf units) to be used in the analysis of the (He, and He) \added{reactions on nuclei} along the N=Z line. These are presented for the conditions relevant to the ) orbits expected from O to Sn. As is the case of the Weisskopf units for electromagnetic transitions, the -WU's will provide a simple, yet robust, measure of isoscalar and isovector pairing collective effects.

    Comments:
    5 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2107.12876 [pdf]
    PLB(2022)·4 citations
  3. 03

    [Submitted on 27 Jul 2021]

    A new empirical formula for {\alpha}-decay half-life and decay chains of Z=120 isotopes

    G. Saxena · A. Jain · P. K. Sharma

    Experimental -decay half-life, spin, and parity of 398 nuclei in the range 50Z118 are utilized to propose a new formula (QF) with only 4 coefficients as well as to modify the Tagepera-Nurmia formula with just 3 coefficients (MTNF) by employing nonlinear regressions. These formulas, based on reduced mass () and angular momentum taken away by the -particle, are ascertained very effective for both favoured and unfavoured -decay in addition to their excellent match with all (Z, N) combinations of experimental -decay half-lives. After comparing with similar other empirical formulas of -decay half-life, QF and MTNF formulas are purported with accuracy, minimum uncertainty and deviation, dependency on least number of fitted coefficients together with less sensitivity to the uncertainties of -values. The QF formula is applied to predict -decay half-lives for 724 favoured and 635 unfavoured transitions having experimentally known -values. Moreover, these available -values are also employed to test various theoretical approaches viz. RMF, FRDM, WS4, RCHB, etc. along with machine learning method XGBoost for determining theoretical -values, incisively. Thereafter, using -values from the most precise theoretical treatment mentioned above along with the proposed formulas, probable -decay chains for Z120 isotopes are identified.

    Comments:
    Accepted in Physica Scripta-IOPscience
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2107.12976 [pdf]
    Phys.Scripta(2021)·31 citations

Affiliations

first authorsco-authorsvia INSPIRE