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Nuclear Theory·nucl-th

Thursday·April 28, 2022

4 papers—2 primary·2 cross-listed

All4Primary2Cross-lists2
  1. 03

    [Submitted on 27 Apr 2022] (cross-list from hep-ph)

    The linear mode analysis and spin relaxation

    Jin Hu🇨🇳

    In this paper, a detailed analysis on normal modes of the linearized Hermite collision operator is presented, which follows from linearizing spin Boltzmann equation for massive fermions proposed in \cite{Weickgenannt:2021cuo} with the non-diagonal part of the transition rate neglected and approximating what we got with a mutilated operator. With the assumption of total angular momentum conservation, the collision term is proved to well describe the equilibrium state and gives proper interpretation for collisional invariants, thus is relevant for the research on local spin polarization. Following the familiar fashion as used in quantum mechanics, we treat the problem of solving normal modes as a degenerate perturbation problem and calculate the dispersion relations for intriguing eleven zero modes, which form one-to-one correspondence to all collisional invariants. We find that the results of spinless modes appearing in ordinary hydrodynamics are consistent with available conclusions in textbooks. As for spin-related modes, we obtain the frequencies up to second order in wave vector and relate them with the dissipation of spin density fluctuation. In addition, the ratio of two relaxation time scales for spin and momentum is shown as a function of reduced mass, which reads that based on present framework spin equilibration is almost as slow as momentum equilibration as far as the strange quark spins in quark gluon plasma (QGP) are concerned.

    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2204.12946 [pdf]
    PRD(2022)·16 citations
  2. 04

    [Submitted on 27 Apr 2022] (cross-list from physics.atom-ph)

    Refined nuclear magnetic dipole moment of rhenium: Re and Re

    Leonid V. Skripnikov · Sergey D. Prosnyak

    The refined values of the magnetic dipole moments of Re and Re nuclei are obtained. For this, we perform a combined relativistic coupled cluster and density functional theory calculation of the shielding constant for the ReO anion. In this calculation, we explicitly include the effect of the finite nuclear magnetization distribution in the single-particle nuclear model using the Woods-Saxon potential for the valence nucleon. By combining the obtained value of the shielding constant ~ppm with the available experimental nuclear magnetic resonance data we obtain the values: , where the first uncertainty is the experimental one and the second is due to theory. The refined values of magnetic moments are in disagreement with the tabulated values, , which were obtained using the shielding constant value calculated for the atomic cation Re rather than the molecular anion. The updated values of the nuclear magnetic moments resolve the disagreement between theoretical predictions of the hyperfine structure of H-like rhenium ions which were based on the tabulated magnetic moment values and available experimental measurements. Using these experimental data we also extract the value of the parameter of nuclear magnetization distribution introduced in [J. Chem. Phys. \textbf{153}, 114114 (2020)], which is required to predict hyperfine structure constants for rhenium compounds.

    Subjects:
    Atomic Physics (physics.atom-ph); Nuclear Theory (nucl-th); physics.chem-ph (physics.chem-ph)
    arXiv:
    2204.13015 [pdf]
    PRC(2022)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE