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Nuclear Theory·nucl-th

Wednesday·November 15, 2023

4 papers—3 primary·1 cross-listed

All4Primary3Cross-lists1
  1. 01

    [Submitted on 14 Nov 2023]

    Quark structure of isoscalar- and isovector-scalar mesons and nuclear matter property

    Yao Ma🇨🇳 · Yong-Liang Ma🇨🇳

    It was found that the isoscalar-scalar and isovector-scalar mesons play significant roles in nuclear matter physics. However, the underlying structures of these resonances are not yet well understood. We construct a three-flavor baryonic extended linear sigma model including both the two- and four-quark constitutes of scalar mesons with respect to the axial transformation and study the nuclear matter properties with relativistic mean field method. The nuclear matter properties at saturation density and hadron spectrums are well reproduced with this model simultaneously and, only the two-quark component of the scalar mesons couple to baryon fields and dominates the nuclear force. A plateau-like structure is found in the symmetry energy of nuclear matter due to the multi-meson couplings, and it's crucial for understanding the neutron skin thickness of and the tidal deformation of neutron star from GW170817. At high density regions, the vector mesons are found to be rather crucial, especially the ones coupling with four-quark configurations. This model can be easily extended to study neutron stars, even with hyperons in their interior.

    Comments:
    Published version
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2311.07899 [pdf]
    PRD(2024)·10 citations
  2. 02

    [Submitted on 14 Nov 2023]

    Light Nuclei Production in Au+Au Collisions at 3 GeV within Thermodynamical Approach: Bulk Properties and Collective Flow

    M. Kozhevnikova🇷🇺 · Yu. B. Ivanov🇷🇺

    We present results of simulations of light-nuclei production in Au+Au collisions at collision energy of 3 GeV within updated Three-fluid Hydrodynamics-based Event Simulator Extended by UrQMD (Ultra-relativistic Quantum Molecular Dynamics) final State interactions (THESEUS). The results are compared with recent STAR data. The light-nuclei production is treated within the thermodynamical approach on equal basis with hadrons. The only additional parameter related to the light nuclei is the energy density of late freeze-out that imitates afterburner stage of the collision because the light nuclei do not participate in the UrQMD evolution. It is found that the late freeze-out is preferable for deuterons, tritons, and He. Remarkably, the He observables are better reproduced with the standard freeze-out. This suggests that the He nuclei better survive in the afterburner stage because they are more spatially compact and tightly bound objects. This is an argument in favor of dynamical treatment of light nuclei. The simulations indicate that the collision dynamics is determined by the hadronic phase. The calculated results reveal not perfect but a good reproduction of the data on bulk observables and directed flow. The elliptic flow turns out to be more intricate.

    Comments:
    12 pages, 8 figures, version published in PRC
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2311.08092 [pdf]
    PRC(2024)·9 citations
  3. 03

    [Submitted on 14 Nov 2023]

    Systematics of neutron emission

    D.S. Delion · S. Ghinescu

    Neutron physics is one of the oldest branches of the experimental nuclear physics,but the investigation of the spontaneous neutron emission from the ground state along the neutron dripline is still at its beginning, in spite of the crucial importance for nuclear astrophysics. The proton dripline is much better investigated and a systematics of spontaneous proton half lives corected by the centrifugal barrier (monopole transitions) is given by the Geiger-Nuttall law , where is the Coulomb parameter characterizing the outgoing Coulomb-Hankel wave in terms of the daughter charge and Q-value. Our purpose is to propose a similar simple systematics of spontaneous neutron half lives, but in terms of the nuclear reduced radius , characterizing the "neutral" outgoing spherical Hankel wave. It turns out that the half life in emission of neutral particles is governed by the scaling law for monopole transitions. We evidence the important role of the angular momentum carried by the emitted neutron. The influence of the neutron wave function generated by a Woods-Saxon nuclear mean field is also analyzed.

    Comments:
    12 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2311.08180 [pdf]
    J.Phys.G(2025)·4 citations
  4. 04

    [Submitted on 13 Nov 2023] (cross-list from hep-ph)

    Isolating perturbative QCD splittings in heavy-ion collisions

    Leticia Cunqueiro🇮🇹 · Daniel Pablos🇮🇹 · Alba Soto-Ontoso🇨🇭 · Martin Spousta🇨🇿 · Adam Takacs🇳🇴 · Marta Verweij🇳🇱

    We define a new strategy to scan jet substructure in heavy-ion collisions. The scope is multifold: (i) test the dominance of vacuum jet dynamics at early times, (ii) capture the transition from coherent to incoherent jet energy loss, and (iii) study elastic scatterings in the medium, which are either hard and perturbative or soft and responsible for jet thermalisation. To achieve that, we analyse the angular distribution of the hardest splitting, , above a transverse momentum scale, , in high- jets. Sufficiently high values of target the regime in which the observable is uniquely determined by vacuum-like splittings and energy loss, leaving the jet substructure unmodified compared to proton-proton collisions. Decreasing enhances the sensitivity to the relation between energy loss and the intra-jet structure and, in particular, to observe signatures of colour decoherence at small angles. At wider angles it also becomes sensitive to hard elastic scatterings with the medium and, therefore, the perturbative regime of medium response. Choosing leads to order one effects of non-perturbative origin such as hadronisation and, potentially, soft scatterings responsible for jet thermalisation. We perform a comprehensive analysis of this observable with three state-of-the-art jet-quenching Monte Carlo event generators. Our study paves the way for defining jet observables in heavy-ion collisions dominated by perturbative QCD and thus calculable from first principles.

    Comments:
    18 pages, 11 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2311.07643 [pdf]
    PRD(2024)·28 citations

Affiliations

first authorsco-authorsvia INSPIRE