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Nuclear Theory·nucl-th

Thursday·August 12, 2021

8 papers—3 primary·5 cross-listed

All8Primary3Cross-lists5
  1. 01

    [Submitted on 10 Aug 2021]

    Nuclear Dynamics and Reactions in the Ab Initio Symmetry-Adapted Framework

    Kristina D. Launey · Alexis Mercenne · Tomas Dytrych

    We review the ab initio symmetry-adapted (SA) framework for determining the structure of stable and unstable nuclei, along with related electroweak, decay and reaction processes. This framework utilizes the dominant symmetry of nuclear dynamics, the shape-related symplectic Sp(3,R) symmetry, which has been shown to emerge from first principles and to expose dominant degrees of freedom that are collective in nature, even in the lightest species or seemingly spherical states. This feature is illustrated for a broad scope of nuclei ranging from helium to titanium isotopes, enabled by recent developments of the ab initio symmetry-adapted no-core shell model expanded to the continuum through the use of the SA basis and that of the resonating group method. The review focuses on energies, electromagnetic transitions, quadrupole and magnetic moments, radii, form factors, and response function moments, for ground-state rotational bands and giant resonances. The method also determines the structure of reaction fragments that is used to calculate decay widths and alpha-capture reactions for simulated x-ray burst abundance patterns, as well as nucleon-nucleus interactions for cross sections and other reaction observables.

    Comments:
    26 pages, 7 figures, 1 table; in Annual Review of Nuclear and Particle Science
    Subjects:
    Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR)
    arXiv:
    2108.04894 [pdf]
    Ann.Rev.Nucl.Part.Sci.(2021)·56 citations
  2. 02

    [Submitted on 10 Aug 2021]

    Emergent symplectic symmetry in atomic nuclei: Ab initio symmetry-adapted no-core shell model

    Kristina D Launey · Tomáš Dytrych · Grigor H Sargsyan · Robert B Baker · Jerry P Draayer

    Exact symmetry and symmetry-breaking phenomena play a key role in gaining a better understanding of the physics of many-particle systems, from quarks and atomic nuclei, through molecules and galaxies. In nuclei, exact and dominant symmetries such as rotational invariance, parity, and charge independence have been clearly established. Beyond such symmetries, the nature of nuclear dynamics appears to exhibit a high degree of complexity, and only now, we show the fundamental role of an emergent approximate symmetry in nuclei, the symplectic Sp(3,R) symmetry, as clearly unveiled from ab initio studies that start from realistic interactions. In this article, we detail and enhance our recent findings presented in Physical Review Letters 124 (2020) 042501, that establish Sp(3,R) as a remarkably good symmetry of the strong interaction, and point to the predominance of a few equilibrium nuclear shapes (deformed or not) with associated vibrations and rotations that preserve the symplectic Sp(3,R) symmetry. Specifically, we find that the structure of nuclei below the calcium region in their ground state, as well as in their low-lying excited states and giant resonances, respects this symmetry at the 60-80% level.

    Comments:
    Part of collection "Role of Symmetries in Nuclear Physics", V.K.B. Kota and A.K. Jain (13 pages, 6 figures, 1 table). arXiv admin note: text overlap with arXiv:1810.05757
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2108.04900 [pdf]
    Eur.Phys.J.ST(2020)·34 citations
  3. 03

    [Submitted on 11 Aug 2021]

    Dynamic modeling for heavy-ion collisions

    Chun Shen🇺🇸

    Recent theory progresses in (3+1)D dynamical descriptions of relativistic nuclear collisions at finite baryon density are reviewed. Heavy-ion collisions at different collision energies produce strongly coupled nuclear matter to probe the phase structure of Quantum Chromodynamics (QCD). Dynamical frameworks serve as a quantitative tool to study properties of hot QCD matter and map collisions to the QCD phase diagram. Outstanding challenges are highlighted when confronting theoretical models with the current and forthcoming experimental measurements from the RHIC beam energy scan program.

    Comments:
    6 pages, 2 figures, contribution to the 19th International Conference on Strangeness in Quark Matter (SQM2021)
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2108.04987 [pdf]
    EPJ Web Conf.(2022)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE