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Nuclear Theory·nucl-th

Wednesday·May 29, 2024

7 papers—5 primary·2 cross-listed

All7Primary5Cross-lists2
  1. 01

    [Submitted on 27 May 2024]

    Heavy-Ion Collisions as Probes of Nuclear Structure

    Nicolas Fortier🇨🇦 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦

    In this work, we perform a model-to-data comparison for U+U and Au+Au collisions performed at RHIC at = GeV and GeV, using a multistage framework. Model calculations for various configurations of U and Au are used to compare with measurements of , the elliptic-flow-momentum correlator, for the first time. It is found that momentum-flow correlations measured in high-energy nuclear collisions, combined with the flow harmonics themselves, are excellent probes of nuclear deformation and of nuclear structure in general.

    Comments:
    7 Pages, 5 Figures, 1 Table
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2405.17526 [pdf]
    PRC(2025)·23 citations
  2. 02

    [Submitted on 28 May 2024]

    Strange quark stars: the role of excluded volume effects

    G. Lugones🇧🇷 · A.G. Grunfeld🇦🇷

    We study cold strange quark stars employing an enhanced version of the quark-mass density-dependent model which incorporates excluded volume effects to address non-perturbative QCD repulsive interactions. We provide a comparative analysis of our mass formula parametrization with previous models from the literature. We identify the regions within the parameter space where three-flavor quark matter is more stable than the most tightly bound atomic nucleus (stability window). Specifically, we show that excluded volume effects do not change the Gibbs free energy per baryon at zero pressure, rendering the stability window unaffected. The curves of pressure versus energy density exhibit various shapes -- convex upward, concave downward, or nearly linear -- depending on the mass parametrization. This behavior results in different patterns of increase, decrease, or constancy in the speed of sound as a function of baryon number density. We analyze the mass-radius relationship of strange quark stars, revealing a significant increase in maximum gravitational mass and a shift in the curves towards larger radii as the excluded volume effect intensifies. Excluded volume effects render our models compatible with all modern astrophysical constraints, including the properties of the recently observed low-mass compact object HESSJ1731.

    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2405.18249 [pdf]
    Universe(2024)·8 citations
  3. 03

    [Submitted on 28 May 2024]

    Construction of continuous collective energy landscapes for large amplitude nuclear many-body problems

    Paul Carpentier🇫🇷 · Nathalie Pillet🇫🇷 · Denis Lacroix🇫🇷 · Noel Dubray🇫🇷 · David Regnier🇫🇷

    Several protocols are proposed to build continuous energy surfaces of many-body quantum systems, regarding both energy and states. The standard variational principle is augmented with constraints on state overlap, ensuring arbitrary precision on continuity. As an illustration, the lowest energy and excited state paths relevant for the Pu asymmetric fission are studied. The scission is clearly signed, with a neutron excess in the neck, the ultimate glue before its rupture. Our approach can potentially connect any couple of Hilbert space states, which opens up new horizons for various applications.

    Comments:
    6 pages, 2 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2405.18312 [pdf]
    PRL(2024)·12 citations
  4. 04

    [Submitted on 28 May 2024]

    Impact of the radial profile of atomic nuclei on observables in high-energy collisions

    Zhengxi Yan🇺🇸 · Jun Xu🇨🇳 · Jiangyong Jia🇺🇸

    In heavy-ion phenomenology, the nucleon density distribution in colliding nuclei is commonly described by a two-parameter Woods-Saxon (WS) distribution. However, this approach overlooks the detailed radial structure in the density distribution that arises from the quantal filling patterns of neutrons and protons. These fine structures, as estimated by the Skyrme-Hartree-Fock density functional, cause slight deviations in heavy-ion observables from the WS baseline, which cannot be captured by simply readjusting the WS parameters. These deviations depend on centrality and observable but often exhibit similar shapes for different nuclei. To fully exploit the exceptional sensitivity of isobar collisions to nuclear structure, such fine structures should be considered.

    Comments:
    5 figures, 6 pages
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2405.18318 [pdf]
    PRC(2024)·1 citation
  5. 05

    [Submitted on 28 May 2024]

    Neutron Data Evaluation of 243Am

    V.M Maslov · V.G. Pronyaev · N.A. Tetereva · K.I. Zolotarev

    The diverse measured data base of n+243Am was evaluated using a statistical theory and genera-lized least squares codes. Consistent description of total, capture and fission measured data provides an important constraint for the inelastic scattering cross section. Important constraints for the measured capture cross section in the 0.15-300 keV energy range come from the average radiative and neutron S0 and S1 strength functions. The evaluated inelastic cross sections of available evaluations are in severe disagreement, predicted change of the inelastic cross section shape at En ~1.5 MeV is attributed to the sharp increase of the level density of the residual odd-even nuclide 241Am due to the onset of three-quasi-particle excitations. The influence of exclusive (n, xnf) pre-fission neutrons on prompt fission neutron spectra (PFNS) and (n, xn) spectra is modelled. Contributions of emissive/non-emissive fission and exclusive spectra of (n, xnf) reactions are defined by a consistent description of the 241Am(n, F), 241Am(n, 2n). Data file is at https://www-nds.iaea.org/minskact/data/original/za095243

    Comments:
    59 pages, 52 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2405.18366 [pdf]
    0 citations
  6. 06

    [Submitted on 27 May 2024] (cross-list from hep-ph)

    Adiabatic Hydrodynamization and the Emergence of Attractors: a Unified Description of Hydrodynamization in Kinetic Theory

    Krishna Rajagopal🇺🇸 · Bruno Scheihing-Hitschfeld🇺🇸 · Rachel Steinhorst🇺🇸

    "Attractor" solutions for the pre-hydrodynamic, far-from-equilibrium, evolution of the matter produced in relativistic heavy ion collisions have emerged as crucial descriptors of the rapid hydrodynamization of quark-gluon plasma (QGP). Adiabatic Hydrodynamization (AH) has been proposed as a framework with which to describe, explain, and predict attractor behavior that draws upon an analogy to the adiabatic approximation in quantum mechanics. In this work, we systematize the description of pre-hydrodynamic attractors in kinetic theory by showing how to use the AH framework to identify these long-lived solutions to which varied initial conditions rapidly evolve, demonstrating the robustness of this framework. In a simplified QCD kinetic theory in the small-angle scattering limit, we use AH to explain both the early- and late-time scaling behavior of a longitudinally expanding gluon gas in a unified framework. In this context, we show that AH provides a unified description of, and intuition for, all the stages of what in QCD would be bottom-up thermalization, starting from a pre-hydrodynamic attractor and ending with hydrodynamization. We additionally discuss the connection between the notions of scaling behavior and adiabaticity and the crucial role of time-dependent coordinate redefinitions in identifying the degrees of freedom of kinetic theories that give rise to attractor solutions. The tools we present open a path to the intuitive explanation of how attractor behavior arises and how the attractor evolves in all stages of the hydrodynamization of QGP in heavy ion collisions.

    Comments:
    66 pages, 22 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2405.17545 [pdf]
    JHEP(2025)·16 citations
  7. 07

    [Submitted on 27 May 2024] (cross-list from hep-ph)

    photoproduction: threshold to very high energy

    Lin Tang🇨🇳 · Yi-Xuan Yang🇨🇳 · Zhu-Fang Cui🇨🇳 · Craig D. Roberts🇨🇳

    A reaction model for photoproduction, which exposes the content of the photon in making the transition and couples the intermediate system to the proton's valence quarks via Pomeron () exchange, is used to deliver a description of available data, viz. both differential and total cross sections from near threshold, where data has newly been acquired, to invariant mass GeV. The study suggests that it is premature to link existing data with, for instance, in-proton gluon distributions, the quantum chromodynamics trace anomaly, or pentaquark production. Further developments in reaction theory and higher precision data are necessary before the validity of any such connections can be assessed.

    Comments:
    8 pages, 6 figures, 4 tables. To appear in Phys. Lett. B
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2405.17675 [pdf]
    PLB(2024)·15 citations

Affiliations

first authorsco-authorsvia INSPIRE