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Nuclear Theory·nucl-th

Tuesday·September 24, 2024

14 papers—6 primary·8 cross-listed

All14Primary6Cross-lists8
  1. 01

    [Submitted on 21 Sept 2024]

    Description of the first order phase transition region of an equation of state for QCD with a critical point

    Jamie M. Karthein🇺🇸 · Volker Koch🇺🇸 · Claudia Ratti🇺🇸

    We map the mean-field Ising model equation of state onto the QCD phase diagram, and reconstruct the full coexistence region in the case of a first order phase transition. Beyond the coexistence line, we maintain access to the spinodal region in the phase diagram, thus providing a description of metastable and unstable phases of matter as well. In this way, our approach includes the super-heated hadronic phase and the super-cooled quark-gluon plasma, which are useful for hydrodynamic simulations of the fireball created in a heavy-ion collision at low collision energy, where a first order phase transition is expected. We discuss the features of the pressure and other thermodynamic observables as functions of temperature and baryonic chemical potential, in particular their behavior in the coexistence region. Finally, we compare our equation of state to other 3D-Ising model ones available in the literature.

    Comments:
    19 pages, 18 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2409.13961 [pdf]
    PRD(2025)·9 citations
  2. 02

    [Submitted on 21 Sept 2024]

    Study of the EEC discrimination power on quark and gluon jet quenching effects in heavy-ion collisions at TeV

    Shi-Yong Chen🇨🇳 · Zi-Xuan Xu🇨🇳 · Ke-Ming Shen🇨🇳 · Wei Dai🇨🇳 · Ben-Wei Zhang🇨🇳 · En-Ke Wang🇨🇳

    We present a systematic investigation of flavor-dependent jet quenching using energy-energy correlators (EEC) in TeV Pb+Pb collisions. Employing the improved SHELL model, which incorporates collisional and radiative energy loss, as well as medium response, we quantify distinct quenching signatures for quark and gluon jets. Key findings include: (1) Pure quark jets exhibit strong EEC enhancement at large angular scales, while gluon jets show a bimodal enhancement pattern at both small and large scales; (2) Dual-shift decomposition in the EEC ratio reveals shifts toward large primarily driven by energy loss, while small-~shifts extend beyond selection bias and indicate intrinsic enhancement of the gluon-initiated jets; (3) Quark jets experience global suppression of averaged energy weight , whereas gluon jets exhibit concentration toward small ; (4) Mechanism decomposition identifies elastic energy loss concentrating toward small , radiative loss dominating quark jet modification, and medium response amplifying large ~enhancement via soft hadrons. The observed flavor dependence in EEC modifications is dominantly driven by intrinsic jet structure differences rather than medium-induced mechanisms. We propose photon-tagged jets as quark proxies and inclusive charged-hadron jets as gluon proxies, finding they reproduce the respective flavor-specific quenching patterns. Our work establishes the EEC as a precision probe of color-charge-dependent jet-medium interactions, providing new constraints for the detailed extraction and QGP tomography, while highlighting the critical role of pre-quenching flavor asymmetries.

    Comments:
    13 pages, 9 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2409.13996 [pdf]
    CPC(2026)·11 citations
  3. 03

    [Submitted on 23 Sept 2024]

    Isospin-symmetry breaking in kaon production: the role of charge-symmetry

    Francesco Giacosa🇵🇱

    An excess of charged versus neutral kaons has been recently reported by the NA61/SHINE collaboration. Similar excesses were also present in previous experiments, even if with larger errors. Models for hadron productions in heavy ion collisions systematically underestimate the measured charge-to-neutral kaon ratio. In this report, we comment on the role of charge-symmetry as a specific isospin transformation. In particular, we show that the ensemble of the initial colliding nuclei being charge-symmetric is sufficient for producing an equal number of charged and neutral kaons in the isospin-symmetry exact limit.

    Comments:
    4 pages. Prepared for the proceedings of the 21st International Conference on Strangeness in Quark Matter (SQM 2024), 2-7/6/2023, Université de Strasbourg, France
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2409.14763 [pdf]
    EPJ Web Conf.(2025)·3 citations
  4. 04

    [Submitted on 23 Sept 2024]

    Heavy Flavour Energy Loss in Small and Large Systems

    Coleridge Faraday🇿🇦 · W. A. Horowitz🇿🇦

    We present suppression results for high- and mesons produced in and collisions at RHIC and LHC. These results are computed using a convolved elastic and radiative energy loss model, which receives small system size corrections to both the elastic and radiative energy loss. We observe that suppression in small systems is almost entirely due to elastic energy loss; furthermore, we find that our model is acutely sensitive to the transition between hard thermal loop and vacuum propagators in the elastic energy loss. Finally, we consider the central limit theorem approximation, which is commonly used to model the elastic energy loss distribution as Gaussian.

    Comments:
    4 Pages, 1 figure, Contribution to Strangeness in Quark Matter 2024
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2409.14886 [pdf]
    EPJ Web Conf.(2025)·1 citation
  5. 05

    [Submitted on 23 Sept 2024]

    Microscopic Study of Spin Transfer in Near-Barrier Nuclear Reactions

    Guillaume Scamps🇫🇷

    In quasi-fission, it is unclear what the interaction between the relative orbital angular momentum and the spin of the fragments is from a microscopic perspective. In macroscopic approaches, it is expected that the large value of the relative orbital angular momentum, of the order of 100~ is transferred through tangential dissipation to the fragments' intrinsic spin by sliding and rolling friction. The goal is to investigate the angular momentum transfer from the initial relative orbital angular momentum to the fragments' spin. How is the transferred spin shared between the fragments? What is the time scale associated with the different mechanisms? How does deformation play a role? A TDDFT simulation in the TDHF-Skyrme framework is used to describe several reactions at different impact parameters with increasing complexity. A method is proposed to study the evolution of the fragments' total spin as a function of time and angular velocity. The increasingly complex reaction allows for careful analysis of all the mechanisms responsible for the transfer of spin. In particular, it is shown that the transfer of nucleons, and neck formation can significantly affect the transfer of spin through tangential friction. Several mechanisms are in contradiction with previous macroscopic calculations. In particular, the spin of the fragments does not always increase during the collision which prevents it from being used to estimate the collision time of the reaction.

    Comments:
    11 pages, 14 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2409.15018 [pdf]
    PRC(2024)·7 citations
  6. 06

    [Submitted on 23 Sept 2024]

    Disentangling nuclear structure through multiparticle azimuthal correlations in high-energy isobar collisions

    Zaining Wang🇨🇳 · Jinhui Chen🇨🇳 · Jiangyong Jia🇺🇸 · Yu-Gang Ma🇨🇳 · Chunjian Zhang🇨🇳

    Event-by-event fluctuations in the amplitudes of flow harmonics offer a novel approach to probing the initial-state characteristics in heavy-ion collisions. In this study, we conduct a systematic investigation of correlations among various flow harmonics utilizing multiparticle cumulants in Ru+Ru and Zr+Zr collisions at 200 GeV within the framework of a multiphase transport model. Correlated nuclear density distributions specific to the isobar systems are incorporated to evaluate the sensitivity of selected observables to variations in nuclear deformation and neutron skin thickness. The analysis reveals that multiparticle azimuthal correlations are responsive to these nuclear structure features, predominantly in the most central collision events. Furthermore, the examined correlations exhibit shallow dependence on the assumed shear viscosity values. These findings provide a quantitative evaluation of the extent to which multiparticle flow observables can discern nuclear structure effects in isobar collisions and offer valuable guidance for future detailed dynamical investigations and experimental measurements.

    Comments:
    8 pgaes, 6 figure, 1 table; Physical Review C acceped version
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2409.15040 [pdf]
    PRC(2026)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE