Nuclear Theory·nucl-th

Thursday·October 31, 2024

10 papers—4 primary·6 cross-listed

05
No-quenching baseline for energy loss signals in oxygen-oxygen collisions
Jannis Gebhard🇩🇪 · Aleksas Mazeliauskas🇩🇪 · Adam Takacs🇩🇪
In this work, we perform computations of inclusive jet, and semi-inclusive jet-hadron cross sections for minimum bias oxygen-oxygen collisions at RHIC and LHC collision energies. We compute the no-quenching baseline for the jet nuclear modification factor $R_{AA}$ and jet-, and hadron-triggered semi-inclusive nuclear modification factors $I_{AA}$ . We do this with state-of-the-art nuclear parton distribution functions (nPDFs), next-to-leading-order matrix elements, parton shower, and hadronization. We observe deviations from unity due to cold-nuclear matter effects, even without quenching. We demonstrate that the parton distribution uncertainties constitute a significant obstacle in detecting energy loss in small collision systems. Hadron-triggered observables are particularly sensitive to uncertainties due to correlations between the trigger and analyzed particles. For jet-triggered $I_{AA}$ , there exists a kinematic window in which nPDF and scale uncertainties cancel dramatically while showing little sensitivity to parton shower and hadronization models, addressing a major limiting factor for energy loss discovery in small systems.
↳ hep-phnucl-exnucl-thJHEP(2025)·19 citations
06
Entanglement Entropy is Elastic Cross Section
Ian Low🇺🇸 · Zhewei Yin🇺🇸
We present universal relations between entanglement entropy, which quantifies the quantum correlation between subsystems, and the elastic cross section, which is the primary observable for high energy particle scattering, by employing a careful formulation of wave packets for the incoming particles. For 2-to-2 elastic scattering with no initial entanglement and subdividing the system along particle labels, we show that both the Rényi and Tsallis entropies in the final states are directly proportional to the elastic cross section in unit of the transverse size for the initial wave packets, which is then interpreted as the elastic scattering probability. The relations do not depend on the underlying dynamics of the quantum field theory and are valid to all orders in coupling strengths. Furthermore, computing quantum correlations between momentum and non-kinematic data leads to entanglement entropies expressed as various semi-inclusive elastic cross sections. Our result gives rise to a novel ``area law'' for entanglement entropy in a two-body system.
↳ hep-thcond-mat.stat-mechhep-phnucl-th+1PRD(2025)·37 citations
07
Dilepton production from moaton quasiparticles
Zohar Nussinov🇺🇸 · Michael C. Ogilvie🇺🇸 · Laurin Pannullo🇩🇪 · Robert D. Pisarski🇺🇸 · Fabian Rennecke🇩🇪 · Stella T. Schindler🇺🇸 · Marc Winstel🇩🇪
The phase diagram of QCD may contain a moat regime in a large region of temperature $T$ and chemical potential $μ \neq = 0$ . A moat regime is characterized by quasiparticle moatons (pions) whose energy is minimal at nonzero spatial momentum. At $μ \neq = 0$ , higher mass dimension operators play a critical role in a moat regime. At dimension six, there are nine possible gauge invariant couplings between scalars and photons. For back-to-back dilepton production, only one operator contributes, which significantly enhances production near a moat threshold. This enhancement is an experimental signature of moatons.
↳ hep-phnucl-thPRL(2025)·17 citations
08
Azimuthal Anisotropy Scaling Functions for Identified Particle and Anti-Particle Species across Beam Energies: Insights into Baryon Junction Effects
Roy A. Lacey (Department of Chemistry, Stony Brook University, Stony Brook, NY)🇺🇸
Azimuthal anisotropy scaling functions are constructed from species-resolved anisotropy measurements in Pb+Pb ( $s_{N N}$ =2.76, 5.02~TeV) and Au+Au ( $s_{N N}$ =7.7--200~GeV) collisions to probe baryon transport and medium response at finite baryon chemical potential ( $μ_{B}$ ). Within this data-driven framework, meson and baryon anisotropies spanning the collective-flow and quenching regimes collapse onto common scaling curves, enabling quantitative separation of viscous attenuation, radial flow, and hadronic re-scattering. The attenuation scale $k_{β}$ exhibits a non-monotonic beam-energy dependence, coincident with the low-energy rise of hadronic re-scattering, consistent with a temperature-dependent specific shear viscosity featuring a near-minimum near the QCD critical region. A charge-odd baryon--antibaryon separation in the effective radial-flow response is negligible at LHC energies but grows toward lower $s_{N N}$ . This species-uniform, baryon-number-scaling separation across $p, Λ, Ξ, Ω$ , and $d$ disfavors a purely hadronic origin and supports junction-driven net-baryon transport at finite $μ_{B}$ , enhancing the experimental visibility of critical dynamics in finite, rapidly evolving systems. Together, these results establish species-resolved scaling functions as a compact and robust tool for constraining baryon stopping, medium opacity, and QGP transport properties.
↳ nucl-exhep-exhep-phnucl-thPLB(2026)·3 citations
09
Nucleon-charmonium interactions from lattice QCD
Yan Lyu🇯🇵 · Takumi Doi🇯🇵 · Tetsuo Hatsuda🇯🇵 · Takuya Sugiura🇯🇵
We present a realistic lattice QCD study on low-energy $N$ - $J / ψ$ and $N$ - $η_{c}$ interactions based on (2+1) flavor configurations with nearly physical pion mass $m_{π} = 146$ MeV. The interactions, extracted from the spacetime correlations of nucleon and charmonium system by using the HAL QCD method, are found to be attractive in all distances and possess a characteristic long-range tail consistent with the two-pion exchange potential. The resulting $S$ -wave scattering lengths are $0.30 (2) (_{- 2}^{+ 0})$ fm, $0.38 (4) (_{- 3}^{+ 0})$ fm, and $0.21 (2) (_{- 1}^{+ 0})$ fm for spin- $3/2$ $N$ - $J / ψ$ , spin- $1/2$ $N$ - $J / ψ$ , and spin- $1/2$ $N$ - $η_{c}$ , respectively. Our results are orders of magnitude larger than those from the photoproduction experiments assuming the vector meson dominance. Our findings may provide deeper understanding of the nonperturbative QCD phenomena ranging from the origin of nucleon mass to the in-medium $J / ψ$ mass modification as well as the properties of hidden-charm pentaquark states.
↳ hep-lathep-phnucl-thPLB(2025)·38 citations
10
Spin Polarized Quasi-particle in Off-equilibrium Medium
Shu Lin🇨🇳 · Jiayuan Tian🇨🇳
It is usually believed that physics in off-equilibrium state characterized by hydrodynamic gradient can be equivalently studied using equilibrium state with suitable metric perturbation. We scrutinize this assumption using chiral kinetic theory in curved space, focusing on spin response to hydrodynamic gradient. Two effects of metric perturbation have been identified: one is to change particle motion by scattering it off the metric fields, which does capture spin response to hydrodynamic gradient, but is limited by kinematic condition in the scattering picture. The other is the genuine effect of off-equilibrium state, which is realizable by mapping the equilibrium state in curved space to flat space through a suitable frame choice. It lifts the kinematic condition in the spin response to hydrodynamic gradient. We classify off-equilibrium effect on spin polarization into modifications of (i) spectral function; (ii) distribution function; (iii) KMS relation. While the last two have been studied using chiral kinetic theory, the first one is usually ignored in kinetic description. We perform a detailed analysis on the first one, finding the radiative correction to spectral function leads to a polarized quasi-particle. The degeneracy of spin responses to different hydrodynamic sources at tree-level is also lifted by radiative correction.
↳ hep-phhep-thnucl-thPRD(2025)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE

No-quenching baseline for energy loss signals in oxygen-oxygen collisions

Entanglement Entropy is Elastic Cross Section

Dilepton production from moaton quasiparticles

Azimuthal Anisotropy Scaling Functions for Identified Particle and Anti-Particle Species across Beam Energies: Insights into Baryon Junction Effects

Nucleon-charmonium interactions from lattice QCD

Spin Polarized Quasi-particle in Off-equilibrium Medium

Affiliations