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Nuclear Theory·nucl-th

Thursday·August 7, 2025

5 papers—1 primary·4 cross-listed

All5Primary1Cross-lists4
  1. 02

    [Submitted on 6 Aug 2025] (cross-list from hep-ph)

    A background-free signal of jet-induced diffusion wake in quark-gluon plasma

    Zhong Yang🇨🇳 · Xin-Nian Wang🇨🇳

    Rapidity asymmetry of jet-hadron correlation has been proposed as a robust signal of dijet-induced diffusion wake in quark-gluon plasma in high-energy heavy-ion collisions. We generalize this observable to other jet configurations such as {\gamma}/Z0-jets and propose a new method to compute the rapidity asymmetry that is free of background. In this new method, the rapidity of the trigger is fixed or restricted to a symmetrical range while the rapidity of the associated jet is varied. The rapidity asymmetry is defined as the difference between the hadron rapidity distribution in the opposite azimuthal direction of the jet (or the same direction of the trigger) with different associated jet rapidities. Since the background in this hadron rapidity distribution with different associated jet rapidity is identical, it will be completely canceled in the rapidity asymmetry. Such background-free rapidity asymmetry caused by jet-induced diffusion wake is demonstrated in CoLBT-hydro simulations of dijets and {\gamma}-jets in Pb+Pb collisions at the LHC, which weakens as hadron pT increases, and subtraction of a p+p baseline has a negligible effect.

    Comments:
    5 pages in RevTex with 4 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2508.04194 [pdf]
    PRC(2026)·4 citations
  2. 03

    [Submitted on 6 Aug 2025] (cross-list from astro-ph.HE)

    Instability windows of relativistic r-modes in stably stratified neutron stars with hyperonic cores

    K. Y. Kraav🇷🇺 · M. E. Gusakov🇷🇺 · E. M. Kantor🇷🇺

    (abridged) -modes are oscillations in rotating stars, primarily restored by the Coriolis force. These oscillations are the most susceptible to the Chandrasekhar-Friedman-Schutz (CFS) instability driven by gravitational wave emission, which makes them promising targets for current and future gravitational wave searches. In order to develop, the instability must overcome dissipative processes within the star. As a result, -modes become unstable only for certain combinations of stellar angular velocity and (redshifted) temperature , defining the so-called instability window on the plane. At high temperatures, bulk viscosity , arising from out-of-equilibrium chemical reactions, is the dominant dissipative agent. Dissipation due to can be greatly enhanced by two independent mechanisms: (1) the presence of hyperons, which significantly increases the bulk viscosity, and (2) the distinctive properties of relativistic -modes in nonbarotropic matter, which further amplify dissipation beyond Newtonian predictions. In this work, we present the first investigation of the combined impact of these mechanisms on -mode instability windows. Our calculations also account for the fact that chemical reactions modify the adiabatic index, in addition to producing bulk viscosity. We further estimate the influence of nucleon pairing effects on the instability windows. By comparing our predictions with recent observations of neutron stars in low-mass X-ray binaries, we find that bulk viscosity in hyperonic matter may provide the necessary dissipation to stabilize -modes in the fastest-spinning and moderately hot stars, even when nucleon superfluidity and superconductivity are taken into account. These results have important implications for the interpretation of observations and for the broader understanding of relativistic -mode physics.

    Comments:
    30 pages, 12 figures, accepted for publication in Physical Review D
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
    arXiv:
    2508.04226 [pdf]
    PRD(2025)·0 citations
  3. 04

    [Submitted on 6 Aug 2025] (cross-list from astro-ph.HE)

    Magnetized Proto-Neutron Stars: Structure and Stability

    Harsh Chandrakar🇮🇳 · Adamu Issifu🇧🇷 · Prashant Thakur🇮🇳 · T. K. Jha🇰🇷 · Aravind Taridalu🇮🇳

    We investigate the evolution of magnetized protoneutron stars (PNSs) through four schematic stages: neutrino trapped, deleptonization, neutrino transparent, and the final cold, catalyzed neutron star (NS). Using a quasi static approximation on the Kelvin Helmholtz timescale, we construct strongly magnetized configurations (magnetic field strengths up to 1e17 G) with the axisymmetric XNS 4.0 code, employing equations of state derived from relativistic mean field theory calibrated with the DDME2 parameter set. We analyze the evolution of the gravitational mass, equatorial radius, stellar deformation, magnetic flux, and the ratio of magnetic to gravitational binding energy as functions of thermodynamic and compositional changes. We find that increasing entropy per baryon and decreasing lepton fraction lead to higher core temperatures, which enhance magnetic deformation, flux confinement, and the magnetic to binding energy ratio. Magnetic field dissipation is most efficient during the deleptonization and neutrino transparent stages, and this process largely determines the observable magnetic field strength of the mature neutron star. This work provides the first general relativistic characterization of how the thermal and compositional evolution of protoneutron stars reshapes magnetic field deformation and energetics across poloidal, toroidal, and mixed field configurations at fixed baryonic mass.

    Comments:
    29 pages, 5 figures, 11 tables
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    2508.04264 [pdf]
    EPJC(2026)·0 citations
  4. 05

    [Submitted on 6 Aug 2025] (cross-list from nucl-ex)

    Experimental Study of Bremsstrahlung Gamma Ray Emission and Short-Range Correlations in Sn+Sn Collisions at 25 MeV/u

    Junhuai Xu · Qinglin Niu · Yuhao Qin · Dawei Si · Yijie Wang · Sheng Xiao · Baiting Tian · Zhi Qin · Haojie Zhang · Boyuan Zhang · Dong Guo · Minxue Fu and 24 other authors

    Short-range correlation (SRC) in nuclei refers to nucleons forming temporally correlated pairs in close proximity, giving rise to the high momentum of the nucleons beyond the Fermi surface. It has been reported that bremsstrahlung production from neutron-proton process in heavy-ion reactions provides a potential probe to the SRC abundance in nuclei. In this paper, we present in detail the precision measurement of bremsstrahlung -rays in + reactions at 25 MeV/u using the Compact Spectrometer for Heavy IoN Experiment (CSHINE). A comprehensive experimental and analysis framework is established to ensure the reliability and robustness of the extracted results. Background contributions are evaluated and subtracted using independent methods, and the consistency of the analysis is systematically validated. By comparing the experimental spectrum with the Isospin-dependent Boltzmann-Uehling-Uhlenbeck simulations, the high momentum tail (HMT) fraction of is derived in Sn nuclei. This work provides a detailed and validated experimental framework for extracting SRC information from bremsstrahlung -ray emission and demonstrates the feasibility of studying nucleon SRCs with high precision in low-energy heavy-ion collisions.

    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2508.04550 [pdf]
    PRC(2026)·7 citations

Affiliations

first authorsco-authorsvia INSPIRE