Nuclear Theory·nucl-th

Friday·December 5, 2025

10 papers—7 primary·3 cross-listed

01
[Submitted on 3 Dec 2025]
Nucleon Short-Range Correlations and High-Momentum Dynamics: Implications on the Equation of State of Dense Matter
Bao-Jun Cai🇨🇳 · Bao-An Li🇺🇸 · Yu-Gang Ma🇨🇳
Nucleon short-range correlations (SRCs) and their high-momentum tails (HMTs) encode key short-range dynamics in nuclei and dense matter. This review provides a concise overview of SRC features relevant to the Equation of State (EOS) of isospin-asymmetric nuclear matter. We summarize empirical and theoretical properties of the single-nucleon momentum distribution $n (k)$ , emphasizing the role of the neutron--proton tensor force, the dominance of correlated np pairs, and the enhancement of minority-species HMTs. Links to nucleon effective E-masses, quasi-deuteron components, and orbital entanglement are briefly noted. We examine how SRC-induced HMTs modify kinetic and potential contributions to the EOS in both non-relativistic and relativistic frameworks, including the softening of the kinetic symmetry energy and departures from the isospin parabolic approximation of asymmetric nuclear EOS. Sensitivity to high-momentum components and generalizations to arbitrary dimensions are also highlighted. Implications for heavy-ion reactions are summarized, including effects on particle yields, collective flows, deeply sub-threshold particle production and hard photon emission, driven by modified initial nucleon momentum distributions and abundant high relative-momentum np pairs during the reaction. Finally, we outline SRC-HMT consequences for neutron-star matter, covering proton fractions, tidal deformabilities, $Z$ -factors, cooling, and the core--crust transition, as well as possible connections to dark-matter interactions in dense environments.
Comments:
Accepted version of a 91-page review article for the Euro. Phys. J. Special Topic on "Probing High-Density Nuclear Matter"
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex)
arXiv:
2512.04206 [pdf]
Euro Phys J. Special Topic (2026): Explor…·9 citations
02
[Submitted on 3 Dec 2025]
Exploring the QCD phase diagram through correlations and fluctuations
Volker Koch🇺🇸 · Volodymyr Vovchenko🇺🇸
The exploration of the Quantum Chromodynamics (QCD) phase diagram is a central goal of relativistic heavy-ion collision experiments. This review focuses on the role of fluctuations and correlations as sensitive probes of the phase structure. We discuss theoretical advancements and experimental methodologies employed to map the QCD phase diagram, highlighting constraints derived from both lattice QCD calculations and existing experimental data. Key observables such as cumulants and factorial cumulants of conserved charges (e.g., net-proton, net-charge) are explored as promising signatures of phase transitions and the QCD critical point. We discuss how these quantities are measured experimentally and compared with theoretical predictions, addressing challenges and best practices for meaningful comparisons. Special attention is given to predictions and current experimental results at high baryon density, including recent findings from the STAR collaboration at RHIC. Finally, we identify open issues and future directions for fluctuation and correlation studies at lower collision energies, relevant for future measurements, for example by the CBM experiment.
Comments:
33 pages, 7 figures, review prepared for EPJ Special Topics "High density nuclear matter", published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2512.04288 [pdf]
Eur.Phys.J.ST(2026)·10 citations
03
[Submitted on 4 Dec 2025]
Quarkyonic Quark-Meson Coupling Model for Nuclear and Neutron Matter
Koichi Saito · Tsuyoshi Miyatsu · Myung-Ki Cheoun
We unite the dual quarkyonic model with the quark-meson coupling (QMC) model to construct a novel nuclear model based on the quark degrees of freedom, which can cover a wide range of nuclear densities, from low density to the crossover region. In the model, the relativistic, gaussian quark wavefunction is used to describe the nucleon structure. We first evaluate the energy density, chemical potential, pressure and sound velocity within the ideal Fermi gas picture. In this case, those physical quantities are discontinuous or divergent at the quark saturation density, where the quarkyonic phase emerges. To remove such singular behavior, we next introduce an infrared regulator, and combine the dual quarkyonic model and the QMC model to include the nuclear interaction -- we call it the quarkyonic quark-meson coupling (QQMC) model. In this model, the quark saturation density depends strongly on the nucleon size. For example, when $r_{p} = 0.6 (0.8)$ fm, where $r_{p}$ is the root-mean-square radius of the proton, the quark saturation density is about $3.6 (1.5) \times ρ_{0}$ in symmetric nuclear matter, where $ρ_{0}$ is the nuclear saturation density. Furthermore, the nuclear interaction plays an important role in considering physical quantities quantitatively. In fact, the QQMC model can produce the sound velocity which is consistent with that inferred from the observed data of several neutron stars. Furthermore, pressure in symmetric or pure neutron matter deduced from the experiments of heavy-ion collisions at high energy can be explained by the QQMC model as well. We discuss in detail the formulation for the QQMC model and the physical quantities calculated by the model.
Comments:
50 pages, 18 figures, 3 tables, accepted for publication in PRC
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2512.04505 [pdf]
4 citations
04
[Submitted on 4 Dec 2025]
Complex-energy eigenvector continuation for nuclear many-body broad resonances
Rongzhe Hu · Nicolas Michel · Zhicheng Xu · Jianguo Li · Furong Xu
Broad resonances are a unique phenomenon in nuclear many-body systems. Theoretical studies usually involve the continuum degree of freedom, which drastically increases the model space of calculations, and may lead to non-convergence or instability of computations. In this paper, we present the extension of the eigenvector continuation (EC) method to the complex-energy space to treat the broad resonances of open quantum systems of nuclei. EC provides an efficient method to predict the solution of a large-space many-body problem within a small subspace. Using only a few bound and narrow resonance solutions as input in EC, we can obtain the solution of a broad resonance. We have applied the complex-energy EC to the broad resonances of $^{4}$ H, four-neutron $^{4} n$ , $^{6}$ He and $^{7}$ He systems.
Comments:
7 pages, 4 figures, 1 table; accepted by Physics Letters B
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2512.04517 [pdf]
PLB(2026)·3 citations
05
[Submitted on 4 Dec 2025]
Static Fission Properties of Even-Even Actinides within the Warsaw Macroscopic-Microscopic Model Using Fourier-over-Spheroid Parameterization
A. Augustyn · T. Cap · R. Capote · M. Kowal · K. Pomorski
A systematic study of fission barrier heights and static properties of even-even actinide nuclei from Th to Cf has been performed within the Warsaw macroscopic-microscopic model using the five-dimensional Fourier-over-Spheroid (FoS) shape parameterization. The use of a large deformation grid, containing about $1.3 \times 1 0^{8}$ points for each nucleus, allows for a refined and numerically complete exploration of the potential energy landscape without dividing the configuration space into subregions or applying interpolation. Barrier heights, extracted via the Immersion Water Flow method, show good agreement with empirical evaluations (including the new IAEA RIPL-4 dataset) with mean deviations below 1 MeV. Special attention is given to the long-debated third, hyperdeformed minimum. For Th isotopes, a shallow but distinct third well appears, whereas it's absent in heavier actinides (U, Pu).
Comments:
12 pages, 6 figures, 1 table
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2512.04739 [pdf]
PRC(2026)·1 citation
06
[Submitted on 4 Dec 2025]
Thermodynamic and transport properties of hot asymmetric nuclear matter within a chiral SU(3) model
Amruta Mishra🇮🇳 · J. Schaffner-Bielich🇩🇪
We investigate the thermodynamic and transport properties in hot nuclear matter accounting for the medium modifications of the nucleons within a chiral SU(3) model including effects from isospin asymmetry. Using the relaxation time approximation, the transport coefficients of the shear viscosity and thermal conductivity are studied. The shear viscosity, $η$ , calculated within the chiral SU(3) model is observed to be smaller than the values calculated for free nucleon gas, whereas the thermal conductivity $κ$ is appreciably larger as compared to the free nucleon gas. The presence of isospin asymmetry in the medium leads to higher values of both the coefficients of shear viscosity ( $η$ ) and thermal conductivity ( $κ$ ), however, the effect is observed to be marginal for $η$ . In the chiral SU(3) model, the effect of isospin asymmetry is observed to be larger for higher values of temperature. For T=150 MeV, there is observed to be a drop in the value of $κ$ as density is increased, contrary to the increase observed for the lower values of temperature, T=50 and 100 MeV. The shear viscosity coefficient to entropy density ratio $η / s$ drops with increasing baryon density that becomes more pronounced at higher temperatures in the chiral SU(3) model as compared to the case of a free nucleon gas. The present study of the thermodynamic as well as transport properties in hot nuclear matter is of relevance for relativistic heavy-ion collisions with different initial isospin asymmetry, in particular for the compressed baryonic matter experiment at the FAIR facility at GSI.
Comments:
31 pages, 10 figures, to be published in Phys. Rev. D
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2512.04820 [pdf]
PRD(2026)·1 citation
07
[Submitted on 4 Dec 2025]
Opacity estimation of OO collision from CoMBolt-ITA hybrid
Seyed Farid Taghavi🇩🇪 · Seyed Mohammad Ali Tabatabaee Mehr🇮🇷
Understanding the effect of system size on the applicability of the hydrodynamic description in heavy-ion physics remains unclear. Recent measurements of OO collisions at the LHC offer a new opportunity to refine our understanding of collectivity because of their intermediate size relative to heavy-ion and small-system collisions, as well as the relatively good control over their initial state. We use the CoMBolt-ITA hybrid model to describe recent OO measurements at the LHC. The model employs TrENTo for the initial state. A combination of the pre-equilibration and hydrodynamized medium stages is modeled consistently by CoMBolt-ITA, which evolves the Boltzmann distribution of massless collective excitations. The afterburner stage is included by employing UrQMD. Using this approach, we test whether the system lies in the regime where its spatial size approaches the mean free path, corresponding to low opacity, or in the opposite limit, where its size exceeds the mean free path sufficiently to enter the fluid-like evolution regime with high opacity. We find that, in light of the data-model comparison and considering the current status of the model, OO collisions with centralities larger than $60%$ gradually leave the domain of fluid-like evolution.
Comments:
6 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2512.05009 [pdf]
PLB(2026)·3 citations
08
[Submitted on 4 Dec 2025] (cross-list from hep-ph)
Nucleon to Roper transition amplitudes and electromagnetic form factors
G. Ramalho🇰🇷
The second excitation of the nucleon, the Roper, has properties differentiated from other low-lying nucleon resonances. Their properties challenge our understanding of the structure of the baryons in terms of the degrees of freedom from QCD. In the present work we discuss the properties of the Roper resonance and the nucleon to Roper electromagnetic transition, based on the quark degrees of freedom, that are expected to dominate for large square momentum transfer $Q^{2}$ . We also discuss the analytic structure of the transition amplitudes in the low- $Q^{2}$ region, and how the contributions of baryon-meson states can help to describe the low and intermediate $Q^{2}$ data, and the nature of the Roper.
Comments:
31 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2512.04493 [pdf]
Acta Phys.Polon.B(2026)·1 citation
09
[Submitted on 4 Dec 2025] (cross-list from astro-ph.HE)
Internal superfluid response and torque evolution in the giant glitch of PSR J1718-3718
Peng Liu · Zhonghao Tu · Jianping Yuan · Ang Li
We investigate the post-glitch rotational evolution of pulsars by analyzing the 2007 giant glitch of PSR J1718 $-$ 3718 using a vortex creep model that incorporates both inward and outward nonlinear vortex motion, along with a time-varying external torque. A comprehensive fitting framework is developed, constrained by prior knowledge of moment of inertia participation from previous glitch studies. We apply a Markov Chain Monte Carlo approach to quantify uncertainties and parameter correlations. The model reproduces the observed timing data and yields physically consistent values for moment of inertia fractions and creep timescales. Our results indicate that inward creep and a long-term change in external torque dominate the observed increase in spin-down rate, pointing to structural changes within the star-likely triggered by a crustquake that initiated both vortex motion and a change in the moment of inertia. We estimate that the glitch involved approximately $2.4 \times 1 0^{12}$ inward-moving vortices and $\sim 142$ crustal plates with a typical size of $\sim 0.03$ km. This study demonstrates that detailed post-glitch modeling of sparse timing data can simultaneously constrain internal superfluid dynamics and external torque evolution, providing a quantitative framework to probe the structural properties of neutron star interiors.
Comments:
9 pages, 3 figures, 4 tables
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2512.04972 [pdf]
1 citation
10
[Submitted on 4 Dec 2025] (cross-list from hep-ph)
Geometry of particle emission in UrQMD Ar+Sc collisions at SPS energies
Barnabas Porfy🇭🇺 · Mate Csanad🇭🇺
Over the past few decades, progress in femtoscopy has been driven by the interplay between experimental measurements and theoretical calculations. Measurements provide data to support the theory, while theoretical predictions guide new measurements. In the recent decade, several experiments have confirmed that the two-particle pion-emitting source is well described by Lévy alpha-stable distributions. To enable theoretical interpretation, phenomenological simulations have been done at RHIC and LHC energies, in large systems such as Au+Au or Pb+Pb, using various available heavy-ion collision models. However, such simulations have not been done in intermediate systems. In this paper, we investigate three-dimensional two-pion pair source distributions from $^{40}$ Ar+ $^{45}$ Sc central collisions at SPS energies, generated with the Ultra-Relativistic Quantum Molecular Dynamics Monte-Carlo event generator. Supplemented by a validation of the simulated hadronic spectra, we find that the pair source can be described with Lévy-stable distributions. We subsequently interpret the physical meaning of the extracted Lévy parameters corresponding to the spatial scale, shape, and strength of the source. Our results form a baseline for future experimental measurements in intermediate systems.
Comments:
12 pages, 8 figures, accepted at Physics Letters B
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2512.05019 [pdf]
PLB(2026)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE