Nuclear Theory·nucl-th

Thursday·November 13, 2025

9 papers—4 primary·5 cross-listed

01
[Submitted on 11 Nov 2025]
Electromagnetic Radiation from Baryon-Rich Matter in Heavy-Ion Collisions
Xiang-Yu Wu🇨🇦 · Charles Gale🇨🇦 · Sangyong Jeon🇨🇦 · Jean-François Paquet🇺🇸 · Björn Schenke🇺🇸 · Chun Shen🇺🇸
We perform a study of electromagnetic radiation in heavy-ion collisions at Relativistic Heavy Ion Collider (RHIC) Beam Energy Scan (BES) and SPS energies using the iEBE-MUSIC framework, which includes 3D dynamical Monte Carlo Glauber initial conditions, MUSIC (3+1)D viscous relativistic hydrodynamics, and the UrQMD hadronic afterburner. The multistage modeling has been calibrated to hadronic data at RHIC-BES energies using a Bayesian analysis. Integrating the thermal photon emission rates with the medium evolution, we study the direct photon yield and elliptic flow and how they vary with collision energy and emission source. We compare with results obtained by the STAR and PHENIX Collaborations. We employ next-to-leading order thermal QCD dilepton emission rates to compute dilepton invariant mass spectra and extract the effective temperature of the quark-gluon plasma at different collision energies.
Comments:
18 pages, 14 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2511.08773 [pdf]
3 citations
02
[Submitted on 12 Nov 2025]
Nuclear shape dynamics in low-energy heavy-ion reactions
K. Hagino
We discuss recent theoretical developments in low-energy heavy-ion reactions. To this end, we put emphasis on a viewpoint of probing nuclear shapes with heavy-ion reactions. We first discuss a single-channel problem with an optical potential model. We particularly discuss a microscopic modeling of the imaginary part of an optical potential as well as a visualization of quantum interference phenomena observed in heavy-ion elastic scattering. We then discuss multi-channel scattering problems, and demonstrate that heavy-ion fusion reactions at energies around the Coulomb barrier are sensitive to the shape of colliding nuclei, providing a powerful tool to probe nuclear shapes. We finally point out that relativistic heavy-ion collisions have large similarities to low-energy heavy-ion reactions in the context of nuclear shape dynamics.
Comments:
10 pages, 10 figures. A talk given at the 29th International Nuclear Physics Conference (INPC2025), Deajon, Korea, May 25-30, 2025. To be published in the EPJ Web of Conferences
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2511.09078 [pdf]
EPJ Web Conf.(2026)·0 citations
03
[Submitted on 12 Nov 2025]
Explaining higher-order correlations between elliptic and triangular flow
Mubarak Alqahtani🇸🇦 · Jean-Yves Ollitrault🇫🇷
The ALICE and CMS Collaborations have analyzed a number of cumulants mixing elliptic flow ( $v_{2}$ ) and triangular flow ( $v_{3}$ ), involving up to $8$ particles, in Pb+Pb collisions at the LHC. We unravel an unexpected simplicity in these complex mathematical quantities for collisions at fixed impact parameter. We show that as one increases the order in $v_{2}$ , for a given order in $v_{3}$ , the changes in the cumulants are solely determined by the mean elliptic flow in the reaction plane, which originates from the almond-shaped geometry of the overlap area between the colliding nuclei. We derive simple analytic relations between cumulants of different orders on this basis. These relations are in good agreement with recent data from the CMS Collaboration. We argue that agreement will be further improved if the analysis is repeated with a finer centrality binning. We make quantitative predictions for cumulants of order 10 which have not yet been analyzed.
Comments:
Published version. 9 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2511.09283 [pdf]
PLB(2026)·1 citation
04
[Submitted on 12 Nov 2025]
Nuclear surface energy solving Hartree-Fock equations with Gogny interactions using Lagrange mesh
Dany Davesne🇫🇷 · Alessandro Pastore🇫🇷 · Jesus Navarro🇪🇸
Hartree Fock equations for finite range interactions in a slab of nuclear matter are presented and solved using an algorithm based on the Lagrange mesh method. This approach is faster and more efficient than the Numerov algorithm commonly used in the literature. Thanks to the improved numerical accuracy, we were able to perform calculations with sufficiently large boxes to minimize the impact of Friedel oscillations on the final results, achieving a precision on the surface energy within a few dozens of keV. Results are presented for several Gogny interactions that have not been previously discussed. In addition, the inclusion of the spin orbit term is examined, showing a net reduction of 1.2-1.9 MeV in the surface energy.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2511.09359 [pdf]
EPJA(2026)·0 citations
05
[Submitted on 11 Nov 2025] (cross-list from nucl-th)
Analytical solution and Lie algebra of the relativistic Boltzmann equation
Yi Wang · Xuan Zhao · Zhe Xu · Jin Hu
In this work, we present a novel and more efficient approach to constructing the relativistic Bobylev, Krook, and Wu (BKW) solution [A. V. Bobylev, Sov. Phys. Dokl. 20, 820 (1976); M. Krook and T. T. Wu, Phys. Fluids 20, 1589 (1977)] of the relativistic Boltzmann equation. Introducing a new ansatz for the distribution function, we demonstrate that within this specific ansatz space, only the equilibrium and BKW-type forms yield exact solutions to the nonlinear Boltzmann equation. Furthermore, we also derive the Lie algebra of invariant transformations admitted by the relativistic Boltzmann equation and show that the corresponding symmetry group transformations can be systematically constructed from this algebra.
Comments:
17 pages, version published in Phys.Rev.D 113 (2026) 11, 116018
Subjects:
Nuclear Theory (nucl-th); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
arXiv:
2511.08652 [pdf]
PRD(2026)·2 citations
06
[Submitted on 11 Nov 2025] (cross-list from hep-ph)
Isospin-breaking in the $π π$ scattering amplitude I: Effects due to the pion mass difference
Gilberto Colangelo🇨🇭 · Martina Cottini🇨🇭 · Jacobo Ruiz de Elvira🇪🇸
This is the first of a series of papers devoted to a detailed analysis of isospin-breaking effects in the $π π$ scattering amplitude and the vector form factor of the pion. Isospin breaking originates from the mass difference between up and down quarks and from electromagnetic effects. The latter can be further split into effects due to the pion-mass difference and the remaining virtual and real photonic effects. In this paper, we derive the modifications to the Roy equations for $π π$ scattering due to the mass difference between the charged and the neutral pion. We solve the equations numerically after matching them to the chiral representation of the $π π$ scattering amplitude evaluated in the same approximation, which is also provided. Numerical results are presented and discussed in detail.
Comments:
46 pages, 8 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2511.08680 [pdf]
JHEP(2026)·7 citations
07
[Submitted on 11 Nov 2025] (cross-list from hep-ph)
Correlations between heavy mesons and the creation of the charmonia, bottomonia, and $B_{c}$ mesons in high energy $pp$ collisions
Jiaxing Zhao🇫🇷 · Joerg Aichelin🇫🇷 · Pol Bernard Gossiaux🇫🇷 · Klaus Werner🇫🇷
The different QCD processes, which can produce a heavy quark-antiquark ( $Q Q ˉ$ ) pair, induce different correlations between the heavy quarks. Employing the EPOS4HQ event generator we study the consequences of these correlations and compare the calculation with experimental results on open and hidden heavy flavour mesons, measured in proton-proton (pp) collisions at RHIC and LHC energies. We find that the measured correlations between heavy mesons are a direct image of the different production mechanisms, which contribute also in a different way to the transverse momentum distribution of open and hidden heavy flavour mesons. The latter are calculated in a Wigner density approach which also enables to reproduce quantitatively the measured $B_{c}$ spectra. This agreement allows conclusions on the spatial distribution of the heavy quark creation processes.
Comments:
14 page, 20 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2511.08796 [pdf]
PRD(2026)·8 citations
08
[Submitted on 12 Nov 2025] (cross-list from hep-ph)
The color force acting on a quark in the pion and nucleon
Wei-Yang Liu🇺🇸 · Edward Shuryak🇺🇸 · Ismail Zahed🇺🇸
In the Operator Product Expansion (OPE) of hard scattering amplitudes, the twist-3 operators describe local colored Lorentz forces acting on a quark, thereby providing a measure of the strength of the gluon fields. Its value is directly accessible from the nucleon twist-3 polarized $g_{2}$ -parton distribution function. In the semiclassical (instanton-based) QCD vacuum models, the leading non-perturbative contribution stems from correlated instanton-anti-instanton pairs, or molecules. We analyze the magnitude of the color force on a struck quark in light hadrons (pion and nucleon), in the context of the instanton liquid model (ILM). We derive explicitly the pertinent form factors associated with the color Lorentz force and show that they are intimately related to the pertinent hadronic gravitational and transversity form factors. Using the ILM enhanced by molecules, we detail the ensuing colored force distribution in the transverse plane for the luminal pions and nucleons. The results for the nucleons are in good agreement with those recently reported from a lattice collaboration.
Comments:
36 pages, 18 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2511.09019 [pdf]
PRD(2026)·4 citations
09
[Submitted on 12 Nov 2025] (cross-list from hep-ph)
Strongly intensive quantities for rapidity correlations of multiplicities
Evgeny Andronov🇷🇺
Studies of the phase diagram of strongly interacting matter created in nuclear collisions are typically carried out using event-by-event fluctuations. Well-known way to disentangle statistical and dynamical fluctuations is to construct special observables named strongly intensive which are free from trivial volume fluctuations. Within the color string model behavior of the second-order strongly intensive quantity $Σ$ is completely determined by the two-particle correlation function from a single string and the string fusion mechanism. In this paper, we analyze third-order strongly intensive observable for forward-backward rapidity correlations and test its behavior within the PYTHIA8 model.
Comments:
submitted to PEPAN
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2511.09259 [pdf]
0 citations

Affiliations

first authorsco-authorsvia INSPIRE