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Nuclear Theory·nucl-th

Monday·November 25, 2024

11 papers—4 primary·7 cross-listed

All11Primary4Cross-lists7
  1. 01

    [Submitted on 22 Nov 2024]

    Transverse and longitudinal spin alignment from color fields in heavy ion collisions

    Di-Lun Yang🇹🇼

    We analyze the spin alignment of vector mesons stemming from spin correlation of the quark and antiquark induced by background color fields in relativistic heavy ion collisions. The quark-coalescence equation relating the collision kernel of the vector-meson kinetic equation to spin alignment is expanded to the relativistic case. Focusing on the color-octet contribution, the spin alignment for mesons from glasma fields with momentum dependence is investigated, where the scenarios for different spin quantization axes are considered. Moreover, we qualitatively analyze the spin alignment from isotropic color fields in the quark gluon plasma phase for comparison. In particular, we propose that the experimental measurement of spin alignment along the beam direction, dubbed as the longitudinal spin alignment, could be useful to identify the dominance of longitudinal spin correlation potentially led by the glasma effect in high-energy nuclear collisions.

    Comments:
    39 pages, 14 figures, typos corrected, minor revisions, published version
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2411.14822 [pdf]
    PRD(2025)·12 citations
  2. 02

    [Submitted on 22 Nov 2024]

    Determining the minimal mass of a proto-neutron star with chirally constrained nuclear equations of state

    Selina Kunkel🇩🇪 · Stephan Wystub🇩🇪 · Jürgen Schaffner-Bielich🇩🇪

    The minimal masses and radii of proto-neutron stars during different stages of their evolution are investigated. In our work we focus on two stages, directly after the supernova shock wave moves outwards, where neutrinos are still captured in the core and the lepton per baryon ratio is fixed to , and a few seconds afterwards, when all neutrinos have left the star. All nuclear equations of state used for this purpose fulfill the binding energy constraints from chiral effective field theory for neutron matter at zero temperature. We find for the neutrino-trapped case higher minimal masses than for the case when neutrinos have left the proto-neutron star. Thermal effects, here in the form of a given constant entropy per baryon , have a smaller effect on increasing the minimal mass. The minimal proto-neutron star mass for the first evolutionary stage with and amounts to and for the stage without neutrinos and to rather independent on the nuclear equation of state used. We also study the case related to an accretion induced collapse of a white dwarf where the initial lepton fraction is and observe large discrepancies in the results of the different tables of nuclear equations of state used. Our finding points towards a thermodynamical inconsistent treatment of the nuclear liquid-gas phase transition for nuclear equations of state in tabular form demanding a fully generalized three-dimensional Gibbs construction for a proper treatment. Finally, we demonstrate that there is a universal relation for the increase of the proto-neutron star minimal mass with the lepton fraction for all nuclear equations of state used.

    Comments:
    29 pages, 8 figures, 2 tables
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    2411.14930 [pdf]
    PRC(2025)·10 citations
  3. 03

    [Submitted on 22 Nov 2024]

    Energy dependence of the deformed nuclear structure at small-

    Heikki Mäntysaari🇫🇮 · Pragya Singh🇫🇮

    We quantify the effect of high-energy JIMWLK evolution on the deformed structure or heavy (Uranium) and intermediate (Ruthenium) nuclei. The soft gluon emissions in the high-energy evolution are found to drive the initially deformed nuclei towards a more spherical shape, although the evolution is slow ,especially for the longest distance-scale quadrupole deformation. We confirm a linear relationship between the squared eccentricity and the deformation parameter in central collisions across the energy range covered by the RHIC and LHC measurements. The applied JIMWLK evolution is found to leave visible signatures in the eccentricity evolution that can be observed if the same nuclei can be collided at RHIC and at the LHC, or in rapidity-dependent flow measurements. Our results demonstrate the importance of including the Bjorken- dependent nuclear geometry when comparing simulations of the Quark Gluon Plasma evolution with precise flow measurements at high collision energies.

    Comments:
    9 pages, 10 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2411.14934 [pdf]
    EPJC(2025)·8 citations
  4. 04

    [Submitted on 22 Nov 2024]

    Ab initio study of the beryllium isotopes Be to Be

    Shihang Shen · Serdar Elhatisari · Dean Lee · Ulf-G. Meißner · Zhengxue Ren

    We present a systematic ab initio study of the low-lying states in beryllium isotopes from 7Be to 12Be using nuclear lattice effective field theory with the N3LO interaction. Our calculations achieve good agreement with experimental data for energies, radii, and electromagnetic properties. We introduce a novel, model-independent method to quantify nuclear shapes, uncovering a distinct pattern in the interplay between positive and negative parity states across the isotopic chain. By combining Monte Carlo sampling of the many-body density operator with a novel nucleon-grouping algorithm, the prominent two-center cluster structures, the emergence of one-neutron halo, complex nuclear molecular dynamics such as {\pi} orbital and {\sigma} orbital, emerge naturally.

    Comments:
    7+9 pages, 4+5 figures
    Subjects:
    Nuclear Theory (nucl-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2411.14935 [pdf]
    PRL(2025)·52 citations

Affiliations

first authorsco-authorsvia INSPIRE