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Nuclear Theory·nucl-th

Thursday·May 7, 2026

9 papers—7 primary·2 cross-listed

All9Primary7Cross-lists2
  1. 01

    [Submitted on 6 May 2026]

    Medium Characterization with Hard Probes: From Cherenkov Light in QED to Jet Drift in QCD

    Hasan R. Rahman🇺🇸

    This dissertation presents a unified framework for medium characterization with hard probes spanning from Cherenkov light in quantum electrodynamics (QED) to jet drift in quantum chromodynamics (QCD). We first develop a dispersive fit to the refractive index of liquid argon (LAr) by incorporating anomalous dispersion at the 106.6 nm resonance for the first time. We show that the angular distribution of Cherenkov radiation is highly sensitive to the peak of the refractive index and contributes a significant excess over isotropic scintillation in certain angular bins. This work is important for precision Particle Identification (PID) for experiments like DUNE and CCM. Transitioning to high-energy nuclear collisions, we utilize ``jet drift'' -- the flow-induced deflection of partons -- as a tomographic probe of the Quark-Gluon Plasma (QGP). Using the Anisotropic Parton Evolution (APE) Monte Carlo simulation across various collision systems (PbPb, AuAu, and UU), we disentangle how the jet modification depends on medium size, temperature, and geometry. We show that jet drift exhibits distinct systematics in observables like the elliptic flow () and dihadron acoplanarity (), which helps disentangle it from conventional energy loss. Together, these studies demonstrate how the angular and kinematic signatures of hard probes revolutionize our ability to resolve the fundamental properties of matter.

    Comments:
    Ph.D. Dissertation
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
    arXiv:
    2605.04393 [pdf]
    0 citations
  2. 02

    [Submitted on 6 May 2026]

    Effects of event-by-event hydrodynamic fluctuations on bottomonium dynamics in Pb--Pb collisions at TeV

    Jiamin Liu🇨🇳 · Yiyun Tang🇨🇳 · Linyuan Wei🇨🇳 · Baoyi Chen🇨🇳

    We investigate the effects of event-by-event hydrodynamic fluctuations on bottomonium nuclear modification factors and elliptic flow in Pb--Pb collisions at TeV. The internal evolution of the heavy quarkonium is described by a time-dependent Schrödinger equation with a temperature-dependent complex heavy-quark potential, while the hot QCD medium evolution is simulated using the iEBE-VISHNU event-by-event viscous hydrodynamic framework. By incorporating both fluctuating and smooth hot media, we find that the bottomonium nuclear modification factor is only marginally affected by event-by-event fluctuations, whereas the elliptic flow is systematically enhanced, with the enhancement growing from the tightly bound to the more weakly bound and . This enhancement arises from the more pronounced participant-plane anisotropy of the fluctuating medium relative to the smooth optical-Glauber reference geometry. These results indicate that a smooth hydrodynamic background reproduces the bottomonium but underestimates its , so that the bottomonium retains a discernible imprint of event-by-event medium fluctuations.

    Comments:
    8 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2605.04558 [pdf]
    0 citations
  3. 03

    [Submitted on 6 May 2026]

    Charged current neutrino processes in hot nuclear matter with a recent Skyrme parametrization constrained by microscopic calculations

    Mingya Duan🇫🇷 · Michael Urban🇫🇷

    Neutrino processes are important in the modeling of supernova explosions, proto-neutron star evolution, and binary neutron star mergers. We study neutrino production and absorption in proto-neutron star and supernova matter and direct Urca neutrino emission of neutron star matter in the framework of the random phase approximation (RPA). As interactions, we employ the recent extended Skyrme parametrization Sky3s whose effective masses and spin-dependent terms were adjusted to microscopic calculations, and the SLy4 parametrization that was used in previous calculations of neutrino rates. The rates obtained for Sky3s differ from those for SLy4 by up to one order of magnitude for some processes and energy regions. We also determine the electron, muon, and proton fractions that lead to a stationary composition of matter for a density above the direct Urca threshold, and find that with Sky3s the standard equilibrium condition is not as badly violated at finite temperature as predicted in the literature. There are also minor differences between the full RPA and the common Landau approximation, but they are probably not significant for astrophysical simulations. We conclude that it would be worthwhile to repeat the calculation of neutrino rates for the use in astrophysical simulations, and the corresponding simulations, with several and better constrained interactions than SLy4, such as Sky3s.

    Comments:
    18 pages, 6 figures; v2: discussion and references added
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    2605.04814 [pdf]
    PRC(2026)·0 citations
  4. 04

    [Submitted on 6 May 2026]

    Nuclear Structure and Shape Evolution of Nd Isotopes

    P. Mohanty · C. Dash · A. Anupam · B. B. Sahu

    In this work, we have analyzed the structural properties of even-even isotopes. For this we have used axially deformed Relativistic Mean Field (RMF) model with PK1 and NL-SH parametrization. In structural properties, We have estimated and analyzed binding energy per nucleon (B.E./A), two neutron separation energy (), differential variation of two neutron separation energy (), quadrupole deformation parameter (), root mean square nuclear charge radius (), neutron skin thickness () and single particle energy (SPE) levels of Nd isotopes. Some bulk properties are also compared with experimentally accessible results and with results of Finite Range Droplet Model (FRDM). To understand the shape evolution around N = 92, the variation of the potential energy curves (PECs) with quadrupole deformation parameter are also investigated. From all the investigations, We observe some sign of stability at N = 92 and shape transitions around it.

    Comments:
    21 pages, 8 figures(Fig. 4 and Fig.8 contains 2 sub figures each)
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2605.04841 [pdf]
    0 citations
  5. 05

    [Submitted on 6 May 2026]

    Nuclear level densities in the relativistic Hartree-Bogoliubov plus combinatorial framework

    Pengxiang Du · Jian Li

    A systematic study of nuclear level densities has been carried out within the relativistic Hartree-Bogoliubov plus combinatorial framework. Calculations were performed for even-even nuclei with available experimental data, based on the relativistic energy density functionals DD-ME2, DD-PC1, and PC-PK1. The overall performance of the model is assessed against experimental data. On this basis, the effects of different functionals, pairing correlations, deformation, and other relevant factors on nuclear level densities are examined. The results show that the present framework provides a good description of the experimental level density and reproduces the s-wave neutron resonance spacings with an accuracy comparable to that of the best existing global models. Furthermore, differences among the adopted relativistic density functionals in the nucleon effective mass at saturated nuclear matter are transmitted to the predicted level densities and constitute the main source of the differences among the results obtained with the three functionals.

    Comments:
    13 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2605.04862 [pdf]
    1 citation
  6. 06

    [Submitted on 6 May 2026]

    Characterizing the quark-hadron mixed phase in compact star cores : sensitivity to nuclear saturation and quark-model parameters at finite-temperature

    Suman Pal🇮🇳 · Gargi Chaudhuri🇮🇳

    A thorough knowledge of the quark-hadron phase transition in hot and dense matter is essential for constraining the equation of state of neutron stars. In this work, we study the thermodynamics of the quark-hadron mixed phase at finite temperature using the Gibbs construction and examine its impact on hybrid star matter. We systematically explore the role of nuclear saturation properties, including the effective nucleon mass, incompressibility, symmetry energy coefficient, and its slope, together with quark matter parameters such as the bag constant and the vector coupling strength. We find that the width of the mixed phase is mainly controlled by the effective mass and symmetry energy, while the roles of incompressibility and symmetry energy slope are comparatively weak, particularly at higher temperatures. Thermal effects substantially modify the phase structure: increasing temperature reduces the mixed-phase width and softens the equation of state in the coexistence region due to Gibbs phase equilibrium constraints. These effects are reflected in the behavior of the speed of sound, the trace anomaly, and its derivative. Variations in the symmetry energy, effective mass, and quark parameters significantly affect the hadron-quark transition, stellar radii, and maximum mass, while finite temperature softens the equation of state and enhances radius jumps in the mixed phase. Strong vector repulsion is essential to reconcile massive pulsar observations with NICER constraints, whereas weaker repulsion favors more compact, low-mass configurations.

    Comments:
    Published 5 May, 2026, Physical Review D
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2605.05005 [pdf]
    PRD(2026)·1 citation
  7. 07

    [Submitted on 6 May 2026]

    Can a hybrid star with constant sound speed parametrization explain the new NICER mass-radius measurements ?

    Suman Pal · Gargi Chaudhuri

    We present a reanalysis of NICER observations of PSR J0740+6620 and PSR J0030+0451 to test the consistency of various nuclear equations of state (EoS) within the framework of hybrid star models. In particular, we examine how different surface temperature models for PSR J0030+0451, categorized as Scenarios A, B, and C, lead to significantly different mass-radius estimates. We perform a comprehensive study constraining the parameters of the constant speed of sound (CSS) model based on representative observational categories. Our findings indicate that for certain hadronic equations of state, including both density-independent and density-dependent cases, the results remain consistent for lower values of the energy density discontinuity, while discrepancies emerge as the discontinuity increases. Scenarios involving large jumps in energy density are generally disfavored by the requirement of supporting massive neutron stars, whereas higher values of the speed of sound in the quark matter phase tend to yield better agreement with observational trends. These results underscore the importance of phase transition characteristics in aligning hybrid star models with current astrophysical observations. We further constrain the CSS parameters using observational data from PSR J0740+6620 and PSR J0952-0607 by computing the maximum mass supported by these parameter sets.

    Comments:
    Published 2025 September 24, The Astrophysical Journal
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2605.05042 [pdf]
    ApJ(2025)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE