Nuclear Theory·nucl-th

Wednesday·September 24, 2025

12 papers—6 primary·6 cross-listed

01
Charm quark evolution in the early stages of heavy-ion collisions
Mayank Singh🇺🇸 · Manu Kurian🇮🇳 · Björn Schenke🇺🇸 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦
Heavy quarks are predominantly generated at the initial stage of relativistic heavy-ion collisions such that heavy flavor observables have the potential to provide information on the pre-equilibrium medium dynamics. In this study, we investigate the sensitivity of D-meson $R_{AA}$ and $v_{2}$ to early-time charm quark dynamics in Pb+Pb collisions at $s_{N N} = 5.02$ TeV. We employ the IP-Glasma+MUSIC+UrQMD framework to model the evolution of the bulk medium. Charm quarks are generated using PYTHIA with nuclear parton distribution functions and evolved using Langevin dynamics within MARTINI. We observe that even though there is significant momentum broadening in the earliest stage, D-meson $R_{AA}$ and $v_{2}$ are only weakly sensitive to pre-equilibrium interactions.
nucl-thhep-phPRC(2026)·9 citations
02
Longitudinal collective modes in relativistic asymmetric magnetized nuclear matter within the covariant Vlasov approach
Aziz Rabhi🇪🇸 · Olfa Boukari🇹🇳 · Sidney S. Avancini🇧🇷 · Constança Providência🇵🇹
The neutron-proton-electron (npe) matter under strong magnetic field is studied in the context of the covariant Vlasov approach. A covariant relativistic approach based on the Vlasov equation is applied to the study of infinite asymmetric magnetized nuclear matter. We use several relativistic mean-field nuclear models with non-linear terms. The dispersion relations for the longitudinal modes are obtained, and the isovector and isoscalar collective modes are determined in a wide range of densities as a function of the isospin asymmetry, momentum transfer, and magnetic field. A strong magnetic field gives rise to the appearance of low-lying isovector modes that propagate in nuclear matter, not present in non-magnetized matter. Neutron-like modes are essentially not affected by the presence of a strong magnetic field. In the presence of a strong magnetic field, Landau quantization modifies the proton-like collective modes, leading to the emergence of new branches associated with distinct Landau levels. These new modes can propagate even at high densities and exhibit isoscalar or isovector character.
nucl-thPRC(2026)·1 citation
03
Magnetization by Rotation: Spin and Chiral Condensates in the NJL Model
Lutz Kiefer🇩🇪 · Ashutosh Dash🇩🇪 · Dirk H. Rischke🇩🇪
The role of spin degrees of freedom in the quark-gluon plasma (QGP) has attracted significant interest in recent years. Spin hydrodynamics extends conventional hydrodynamics by incorporating spin via the spin tensor. In the mean-field limit of the Nambu-Jona-Lasinio (NJL) model under rigid rotation, spin degrees of freedom manifest naturally as axial-vector, or spin, condensate. We investigate the interplay between chiral and spin condensates in this framework. While rotation typically suppresses the formation of a chiral condensate, the presence of a spin condensate may counteract this effect, enhancing the chiral condensate. Moreover, it can alter the nature of the chiral transition from second to first order.
nucl-thhep-thPRD(2026)·3 citations
04
Stochastic Mean-Field Theory and Applications to Multinucleon Transfer and Kinetic Energy Dissipation Processes in Heavy-Ion Collisions
S. Ayik · M. Arik · O. Yilmaz · A.S. Umar
In this Review article, a brief description of the stochastic mean-field theory (SMF) for describing reaction dynamics in low-energy heavy-ion collisions at bombarding energies in the vicinity of the Coulomb barrier is presented. In these collisions, as a result of strong Pauli blocking, binary nucleon collisions do not have a significant effect on the dissipation and fluctuations. At low energies, the mean-field fluctuations, due to initial correlations, have a dominant effect on fluctuations of macroscopic variables. The SMF theory proposes the determination of an ensemble of single-particle density matrices by specifying random initial fluctuations according to a distribution law. Employing an ensemble of single-particle density matrices, not only the mean values but also the distribution functions of the one-body observables can be determined. If the di-nuclear structure is maintained in heavy-ion collisions, such as deep inelastic collisions and fast quasi-fission reactions, a much simpler description of the reaction mechanism can be derived in terms of several macroscopic variables such as mass and charge asymmetry, and relative linear and relative angular momentum. In this case, by geometric projection of the SMF equations, it is possible to derive the quantal Langevin equations for macroscopic variables. As an application of quantal transport description, an analysis of multinucleon transfers and kinetic energy dissipation and fluctuations is presented for selected quasi-fission reactions.
nucl-thEPJA(2026)·1 citation
05
Fine-tuning of the $K ˉ N N$ and $K ˉ K ˉ N$ quasi-bound state calculations
N.V. Shevchenko🇨🇿
Fine-tuning of the binding energies and widths of the quasi-bound states in three-body systems consisting of antikaon(s) and nucleon(s) was performed. Dynamically exact three-body Faddeev-type AGS equations with three coupled particle channels were solved for the description of the $K ˉ N N$ and $K ˉ K ˉ N$ systems in different spin states. New models of the antikaon-nucleon and pion-nucleon interactions were constructed, and together with our best versions for the remaining potentials were used as input. The characteristics of the quasi-bound $K^{-} pp$ state calculated with our new one-pole $K ˉ N - π Σ - π Λ$ potential reproduces the experimental data from the E15 J-PARC experiment.
nucl-thPRC(2025)·4 citations
06
A novel filtering method for generating desired density profiles of colliding nuclei
Xilong Xiang🇨🇳 · Manzi Nan🇨🇳 · Pengcheng Li🇨🇳 · Yongjia Wang🇨🇳 · Ling Liu🇨🇳 · Qingfeng Li🇨🇳
Accurate modeling of the density profile is essential for studying heavy-ion collisions (HICs) with a transport model. Within the framework of the quantum molecular dynamics (QMD)-type model, a novel method for generating desired nuclear density distributions based on Fourier series expansion is proposed. This new initialization method is further incorporated into the ultrarelativistic quantum molecular dynamics model, and the bubble-like density distribution of $^{96}$ Ru is constructed. Then, by simulating $^{96}$ Ru+ $^{96}$ Ru collisions at $E_{lab} = 1500$ MeV/nucleon with different equations of state (EoS) and initialization methods, the effects of the initial density distribution on the final state observables and the constrained information of EoS are analyzed. It is found that $^{96}$ Ru nuclei with a bubble density profile lead to an increased maximum compression during the collision, which in turn enhances the collective flow. Moreover, a relatively stiff EoS with $K_{0} > 280$ MeV is favored for the conventional Woods-Saxon type density profile, whereas an EoS with $K_{0}$ =200-280 MeV is supported when a bubble-like density profile is employed. These results demonstrate that the initial nuclear density distribution plays a non-negligible role in dynamical observables and EoS constraints. The proposed method thus provides a powerful tool for constructing exotic profiles and investigating nuclear structure effects in HICs.
nucl-thPRC(2026)·1 citation
07
A Quantum Computational Determination of the Weak Mixing Angle in the Standard Model
Qiaofeng Liu🇺🇸 · Ian Low🇺🇸 · Zhewei Yin🇺🇸
The weak mixing angle $s_{W}$ is a fundamental constant in the Standard Model (SM) and measured at the $Z$ boson mass to be $s_{W}^{2} (m_{Z}) = 0.23129 \pm 0.00004$ in the $MS$ renormalization scheme, where $m_{Z} = 91.2 GeV$ . On the other hand, non-stabilizerness - the magic - characterizes the computational advantage of a quantum system over classical computers. We consider the production of magic from stabilizer initial states, which carry zero magic, in the 2-to-2 scattering of charged leptons in the SM at the tree level, which is mediated by the photon and the $Z$ boson. Using the second order stabilizer Rényi entropy, and averaging over all 60 initial stabilizer states and the scattering angle, we compute and minimize the magic production as a function of $s_{W}^{2}$ in the Møller scattering $e^{-} e^{-} \to e^{-} e^{-}$ , which is free of kinematic thresholds. At the centre-of-mass energy $s = m_{Z}$ , there is a unique minimum in magic production at $s_{W}^{2} (m_{Z}) = 0.2317$ , which agrees with the measured $s_{W}^{2} (m_{Z})$ at the sub-percent level. At higher energies, the magic-minimizing $s_{W}^{2}$ continues to agree with the empirical value at the percent level or better, up to 10 TeV. The finding suggests the electroweak sector of the SM tends to generate minimal quantum resources from the computational viewpoint.
↳ hep-phhep-exhep-thnucl-th+123 citations
08
Probing Quark Electromagnetic Properties via Entangled Quark Pairs in Fragmentation Hadrons at Lepton Colliders
Qing-Hong Cao🇨🇳 · Guanghui Li🇨🇳 · Xin-Kai Wen🇨🇳 · Bin Yan🇨🇳
Electromagnetic dipole interactions of light quarks induce distinct spin correlations in quark pairs produced at lepton colliders, favoring entangled spin-triplet state aligned along the $z^$ axis or spin-singlet state. These correlations lead to unique $cos (ϕ_{1} - ϕ_{2})$ azimuthal asymmetries in inclusive $π^{+} π^{-}$ -dihadron pair production and in back-to-back hadron pairs ( $π π, K π, K K$ ), which are absent in the SM. Using published Belle and BaBar measurements together with projected sensitivities based on ratios of azimuthal asymmetries, we demonstrate that these measurements provide significant constraints on light-quark dipole couplings, with a reduced dependence on poorly known nonperturbative fragmentation functions and free from contamination by other new physics effects. This approach offers a clean and novel probe of light-quark dipole interactions in collider experiments.
↳ hep-phhep-exnucl-exnucl-thRept.Prog.Phys.(2026)·17 citations
09
Global Deep Neural Network Modeling of Compton Form Factors Constrained from Local $χ^{2}$ Maps Fits
L. Calero Diaz🇺🇸 · D. Keller🇺🇸
Over the past two decades, intense experimental efforts have focused on measuring observables that contribute to a three-dimensional description of the nucleon. Generalized Parton Distributions provide complementary insights into the internal structure and dynamics of hadrons, including information about the orbital angular momentum carried by quarks. The most direct process to access these distributions is Deeply Virtual Compton Scattering, in which the cross section can be expressed in terms of Compton Form Factors. These quantities are defined as convolutions of the Generalized Parton Distributions with coefficient functions derived in perturbative Quantum Chromodynamics. We extract the Compton Form Factors from Deeply Virtual Compton Scattering data collected at Jefferson Lab, including the most recent measurements in Hall A, using a novel local fitting technique based on $χ^{2}$ mapping to constrain the real parts of the Compton Form Factors $H, E$ and $H$ . They are determined independently in each kinematic bin for the unpolarized beam-target configuration under the twist-2 approximation, following the formalism developed by Belitsky, Müller, and Kirchner. The extracted Compton Form Factors are then used to train and regularize a deep neural network, enabling a global determination of their behavior with minimal model dependence. This procedure is validated and systematically studied using pseudodata generated with kinematics matching those of the experimental measurements.
↳ nucl-exnucl-thPRD(2025)·9 citations
10
Listening to the long ringdown: A novel way to pinpoint the EOS in neutron-star cores
Christian Ecker🇩🇪 · Tyler Gorda🇺🇸 · Aleksi Kurkela🇳🇴 · Luciano Rezzolla🇩🇪
Gravitational waves (GWs) from binary neutron star (BNS) merger remnants complement constraints from the inspiral phase, mass-radius measurements, and microscopic theory by providing information about the neutron-star equation of state (EOS) at extreme densities. We perform general-relativistic simulations of BNS mergers using EOS models that span the uncertain high-density regime. We find a robust correlation between the ratio of energy and angular momentum lost during the late-time post-merger GW signal - the long ringdown - and the EOS at the highest densities in neutron star cores. Applying this correlation to post-merger GW signals reduces EOS uncertainty at several times saturation density, where no direct constraints currently exist.
↳ astro-ph.HEgr-qchep-phnucl-thEPJ Web Conf.(2026)·0 citations
11
Soret and Dufour effects in hot and dense QCD matter
Kamaljeet Singh🇮🇳 · Kangkan Goswami🇮🇳 · Raghunath Sahoo🇮🇳
The gradients act as invisible engines of transport, converting microscopic imbalances into macroscopic flows, and thus providing deep insights into the dynamics of physical systems. Thermal gradients do not merely drive the flow of heat, but they also set the microscopic constituents of the system into motion. In such scenarios, the constituents of the system not only transport energy but also diffuse collectively under the influence of these gradients. For the very first time, we present a first-principles investigation of the Soret and Dufour effects in hot and dense quantum chromodynamics (QCD) matter. We use the relativistic Boltzmann transport equation under the relaxation time approximation. By incorporating chemical potential and temperature gradients into the kinetic theory framework, we derive explicit expressions for the Dufour coefficient, which quantifies the heat flow due to concentration gradients, and the Soret coefficient, which describes the particle diffusion induced by thermal gradients. These coupled-transport phenomena are traditionally studied in multi-component classical systems at low energy scales. In this study, we follow quasiparticle models for the deconfined phase and the hadron resonance gas model for the confined hadronic phase in the context of heavy-ion collisions. This study provides novel insights into the thermo-diffusion and diffusion-thermo phenomena and opens avenues for incorporating such effects in hydrodynamic modeling and transport simulations of QCD matter.
↳ hep-phhep-exhep-thnucl-ex+1PRD(2026)·1 citation
12
r-Process Nucleosynthesis With Ab Initio Nuclear Masses Around The N=82 Shell Closure
Jan Kuske · Takayuki Miyagi · Almudena Arcones · Achim Schwenk
Our understanding of the origin of heavy elements beyond iron relies on the rapid neutron capture process (r-process), which accounts for roughly half of their cosmic abundance. However, the extreme neutron-rich conditions required for the r-process involve many nuclei that remain experimentally inaccessible, making theoretical predictions essential. We explore the impact of nuclear masses calculated with the ab initio valence-space in-medium similarity renormalization group, focusing on the region around the N = 82 shell closure. We show for the first time that such ab initio mass calculations can be used to refine r-process predictions compared to global, but more phenomenological mass models. With the ab initio masses, the waiting point of the second r-process peak is strengthened, which leads to an overall slower nucleosynthesis flow, lower abundances of nuclei beyond the peak, and a stronger shift of the third r-process peak.
↳ astro-ph.HEnucl-exnucl-thPRL(2026)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE