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Nuclear Theory·nucl-th

Wednesday·March 4, 2026

9 papers—4 primary·5 cross-listed

All9Primary4Cross-lists5
  1. 01

    Spin hydrodynamics on a hyperbolic expanding background

    Rajeev Singh🇷🇴 · Alexander Soloviev🇸🇮

    We study relativistic spin hydrodynamics on the hyperbolic flow background recently identified by Grozdanov. This background corresponds to an -invariant, transversely expanding solution with finite spacetime support in Minkowski space, in contrast to the well-known Gubser flow which possesses symmetry and infinite transverse extent. Working within the formulation of perfect-fluid spin hydrodynamics, we derive the exact evolution equations for all spin components of the spin potential on the background. We find that the enhanced early-time expansion rate and the presence of a causal edge lead to a stronger localization of spin dynamics compared to the Gubser case. Remarkably, the azimuthal component of the spin potential oscillates as it decays in the forward lightcone, in stark contrast to the Gubser flow. Thus, our results establish the flow as a distinct and physically meaningful benchmark for studying spin dynamics in expanding relativistic fluids with finite spacetime support.

    nucl-thhep-phhep-th4 citations
  2. 02

    Unshadowing the constituent quark number scaling of harmonic flow in heavy-ion collisions

    Tom Reichert🇨🇭 · Iurii Karpenko🇨🇿

    Constituent quark number scaling of elliptic flow has been proposed as one key observable to identify the phase transition or the absence of the Quark-Gluon Plasma (QGP) in heavy-ion collisions. At the fixed target program at RHIC the STAR collaboration has recently reported that NCQ scaling breaks when decreasing the collision energy from to GeV. However, the generation of elliptic flow is dominated by a highly intricate interplay of spectator shadowing, squeeze-out and geometry dependent hadron emission governed by their cross sections. Therefore in this article we will disentangle the shadowing contribution from the harmonic flow signal of the particle emitting source, effectively ``unshadowing'' the source. We introduce Fourier coefficients that quantify the azimuthal absorption rate of hadrons decoupling from the system. We benchmark the derived results using a toy model based on a ballistic Glauber description of the penetrating nuclei and calculate how shadowing qualitatively alters the constituent quark number scaling of the hadron emitting source. The results are thus relevant for interpreting recent STAR measurements as well as the upcoming measurements by CBM at FAIR.

    nucl-thnucl-ex0 citations
  3. 03

    Effects of isovector spin-orbit interaction on the charge-weak form factor difference in Ca, Pb, Zr and Ni

    Tong-Gang Yue🇨🇳 · Zhen Zhang🇨🇳 · Lie-Wen Chen🇨🇳

    The nucleon spin-orbit interaction is a cornerstone of nuclear structure theory, yet its isospin dependence remains insufficiently constrained within modern nuclear energy density functional (EDF) theory. It was recently shown that, within the framework of extended Skyrme EDFs, the charge-weak form factor difference in Ca exhibits remarkable sensitivity to the effective isovector spin-orbit (IVSO) interaction, whereas in Pb is much less sensitive to this channel. Extending this analysis to other nuclei, we find that Zr, with its ten spin-orbit unpaired neutrons, displays a sensitivity to the IVSO strength similar to that of Ca, arising from modifications to the central mean-field potential rather than the one-body spin-orbit potential. In contrast, Ni, like Pb, remains largely insensitive to the IVSO interaction. This structure-driven distinction suggests an experimental strategy: future parity-violating electron scattering measurements, e.g., the MREX experiment at the MESA facility, on Ca and Zr would help constrain the effective IVSO strength, while measurements on Pb and Ni can provide a cleaner probe of the density dependence of the symmetry energy with reduced IVSO sensitivity.

    nucl-thastro-ph.HEhep-phnucl-exParticles(2026)·0 citations
  4. 04

    Relativistic distorted-wave analysis of the missing-energy spectrum measured with monochromatic -C interactions at JSNS

    J. M. Franco-Patino · J. García-Marcos · V. Belocchi · M. B. Barbaro · G. Co' · R. González-Jiménez

    Recently, the JSNS collaboration measured for the first time the missing-energy distribution of C using a monochromatic neutrino beam coming from kaon decays at rest. In this work we present the results of an analysis of this spectrum using the relativistic distorted-wave approach. A new parameterization of the spectral function for neutrons in C, which incorporates detailed information from experiments with high missing-energy resolution has been used. The role of the recoil of the residual nucleus, final-state interactions, and neutrino event generators are discussed.

    nucl-thnucl-exPRD(2026)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE