Nuclear Theory·nucl-th

Wednesday·December 24, 2025

15 papers—9 primary·6 cross-listed

01
[Submitted on 22 Dec 2025]
Kinetic theory and the speed of sound in dense matter
Michał Marczenko🇵🇱
We discuss a constraint on the speed of sound, $c_{s}^{2}$ , derived from relativistic kinetic theory and show how it can be expressed in terms of the average sound speed, $⟨ c_{s}^{2} ⟩$ . This reformulation highlights the interplay between instantaneous and integrated stiffness of the equation of state and allows the kinetic-theory bound to be visualized as a restriction in the $c_{s}^{2}$ - $⟨ c_{s}^{2} ⟩$ plane.
Comments:
proceedings of The 29th International Nuclear Physics Conference (INPC 2025), Daejeon, Korea, 25-30 May, 2025
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2512.19770 [pdf]
EPJ Web Conf.(2026)·0 citations
02
[Submitted on 23 Dec 2025]
Nuclear Responses to Two-Body External Fields Studied with the Second Random-Phase-Approximation
Futoshi Minato
This study investigates nuclear responses to two body external fields, interpreted as double phonon excitations, within the subtracted second random phase approximation (SSRPA) for 16O and 40Ca. To clarify the underlying characteristics of these modes, Hartree Fock(HF) and SSRPA with the diagonal approximation are first examined. The resulting strength distributions are nearly identical, indicating that residual interactions in the 1p1h sector contribute only weakly. This behavior contrasts with that of one body excitations, where coupling between 1p1h and 2p2h configurations is essential for generating collectivity. In the full SSRPA calculation, which incorporates the residual interaction among 2p2h configurations, the strength distributions are substantially modified. The double IS 0+ and 2+ modes show pronounced redistribution, with peaks shifted to lower energies and additional strength emerging at higher energies, whereas the double IV 1- mode shifts predominantly to higher energies due to a largely repulsive interaction, resulting in a resonance around twice the peak energy of the single giant dipole resonance. Analysis of single transition amplitudes reveals that low lying resonances are formed coherently through constructive neutron-neutron, proton-proton, and neutron-proton configurations, while high-lying resonances are dominated by neutron-proton configurations, reflecting their higher state density. These results demonstrate that double-phonon excitations cannot be described by simple folding of one-body responses; a fully microscopic treatment of 2p2h mixing, as provided by SSRPA, is essential.
Comments:
Accepted for publication in Physical Review C. 17 pages, 14 figures, 7 tables
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2512.19961 [pdf]
PRC(2026)·0 citations
03
[Submitted on 23 Dec 2025]
Glauber-theory calculations of high-energy nuclear scattering observables using variational Monte Carlo wave functions
W. Horiuchi🇯🇵 · Y. Suzuki🇯🇵 · R.B. Wiringa🇺🇸
Experiments using intermediate- to high-energy radioactive nuclear beams present numerous findings. Extracting important properties of physical observables relies on a firm theoretical analysis. Though Glauber theory is believed to work well, no convincing calculation has so far been done. We perform ab initio Glauber theory calculations of both elastic differential cross sections and total reaction cross sections for p+12C, 12C+12C, and 6He+12C systems. The wave functions of both 6He and 12C are generated by variational Monte Carlo calculations with spatial and spin-isospin correlations induced by realistic two- and three-nucleon potentials. Glauber's phase-shift function is computed by Monte Carlo integration up to all orders of nucleon-nucleon multiple scatterings. We show an excellent performance of the Glauber description to the selected data on the above systems. We also find that the cumulant expansion of the phase-shift function converges rapidly up to the second order for the above systems. This finding will open up interesting applications for the analysis of high-energy nuclear experiments.
Comments:
6 pages, 4 figures, to appear in Phys. Rev. Lett
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2512.20095 [pdf]
PRL(2026)·5 citations
04
[Submitted on 23 Dec 2025]
Glauber-theory analysis of nuclear reactions on 12C target with variational Monte Carlo wave functions
W. Horiuchi · Y. Suzuki · R.B. Wiringa
The application of Glauber theory has been playing an increasingly important role with the study of unstable or exotic nuclei. Its adaptation to medium and high-energy nucleus-nucleus collisions is severely limited because one has to evaluate the matrix elements of multiple-scattering operators. The extraction of physical observables has been done using 'approximate' Glauber theory whose validity is hard to evaluate. We perform a full calculation of the matrix elements using Monte Carlo integration and analyze the elastic differential cross sections and the total reaction cross sections for p+12C, 4,6He+12C, and 12C+12C collisions. We use the variational Monte Carlo wave functions for 4,6He and 12C obtained by using realistic two- and three-nucleon potentials. We demonstrate the performance of the Glauber-theory calculations by comparing with available experimental data. We further discuss the accuracy of the conventional approximate methods in the light of the cumulant expansion for Glauber's phase-shift function.
Comments:
22 pages, 21 figures, to appear in Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2512.20100 [pdf]
PRC(2026)·4 citations
05
[Submitted on 23 Dec 2025]
Challenge of nuclear transmutation in heavy-ion colliders
I.A. Pshenichnov (1 and 2)🇷🇺 · S.D. Savenkov (1 and 2)🇷🇺 · A.O. Svetlichnyi (1 and 2) ((1) Institute for Nuclear Research, Russian Academy of Sciences, Moscow, Russia, (2) Moscow Institute of Physics and Technology, Dolgoprudny, Russia)🇷🇺
We investigate the production of secondary nuclei in the hadronic fragmentation and electromagnetic dissociation (EMD) of $^{20}$ Ne beams at the LHC and $^{124}$ Xe beams at NICA. For light nuclei at LHC energies, our calculations show that hadronic interactions are the dominant channel for nuclear transmutation. This contrasts with the previously established dominance of EMD in $^{208}$ Pb- $^{208}$ Pb collisions. For $^{20}$ Ne- $^{20}$ Ne collisions at $s_{NN} = 5.36$ TeV, we provide calculated cross sections and momentum distributions of produced nuclei such as $^{4}$ He, $^{12}$ C, $^{14}$ N, and $^{16}$ O. These results are essential for assessing potential contamination of the $^{20}$ Ne- $^{20}$ Ne event sample by collisions involving other nuclear species. Secondary nuclei will be also produced in the EMD of $^{124}$ Xe beams at NICA, but they will not contaminate $^{124}$ Xe- $^{124}$ Xe data.
Comments:
8 pages, 2 figures, Talk given at 22nd Lomonosov Conference on Elementary Physics, Moscow, August 21-27, 2025
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2512.20139 [pdf]
0 citations
06
[Submitted on 23 Dec 2025]
Proton-neutron correlations in baryon-number fluctuations near the liquid-gas transition
Michał Marczenko🇵🇱
We study net-baryon number density fluctuations in isospin-symmetric matter near the nuclear liquid-gas phase transition using the parity doublet model. We analyze second-order susceptibilities of net-proton and net-neutron numbers and their correlations. We show that proton-neutron correlations are nontrivial and lead to qualitative differences between net-proton and net-baryon fluctuations. We further investigate factorial cumulants and demonstrate that the differences between baryon- and proton-number factorial cumulants are governed by proton-neutron correlations. Our results highlight the importance of interaction-driven correlations for interpreting fluctuation measurements near the liquid-gas critical endpoint.
Comments:
proceedings of The 29th International Nuclear Physics Conference (INPC 2025), Daejeon, Korea, 25-30 May, 2025
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2512.20258 [pdf]
EPJ Web Conf.(2026)·1 citation
07
[Submitted on 23 Dec 2025]
Towards compressed baryonic matter densities: thermodynamics and transport coefficients
Anand Rai🇮🇳 · Dani Rose J Marattukalam🇮🇳 · Prasanta Murmu🇮🇳 · Ashutosh Dwibedi🇮🇳 · Rishabh Sharma🇮🇳 · Sabyasachi Ghosh🇮🇳
We study the thermodynamic and transport properties of hot and dense quantum chromodynamic matter expected to be produced in low-energy heavy-ion collisions, using three different effective quantum chromodynamic frameworks: the Nambu--Jona-Lasinio model, the chiral effective model, and the hadron resonance gas model. We briefly outline the theoretical formulation of thermodynamic quantities and transport coefficients within these approaches, where quarks are treated with effective masses in the Nambu--Jona-Lasinio and chiral effective models, and hadronic degrees of freedom are employed in the hadron resonance gas model. The transport coefficients are evaluated using the Boltzmann transport equation in the relaxation-time approximation. Following the theoretical overview, we present a comprehensive analysis of the behavior of these quantities as functions of the baryon chemical potential or net baryon density. The Lorenz ratio $κ / (σ T)$ is found to increase rapidly-indicating a strong violation of the Wiedemann-Franz law in the low- $μ_{B}$ regime--while approaching the universal value at higher baryon chemical potentials or densities. The shear-viscosity-to-entropy-density ratio $η / s$ remains nearly constant at low $μ_{B}$ but exhibits a gradual increase as $μ_{B}$ grows. We also discuss the qualitative similarities of these trends with those observed in the electron-hole plasma of graphene, an emergent quasi-relativistic system characterized by massless energy-momentum dispersion.
Comments:
16 pages, 8 figures. Comments and suggestions are welcome
Subjects:
Nuclear Theory (nucl-th); Strongly Correlated Electrons (cond-mat.str-el)
arXiv:
2512.20282 [pdf]
EPJC(2026)·4 citations
08
[Submitted on 23 Dec 2025]
Studying nuclear medium modification using the Gerasimov-Drell-Hearn sum rule
A. Deur🇺🇸 · M. M. Dalton🇺🇸 · S. Širca🇸🇮
The Gerasimov-Drell-Hearn sum rule is a generic relation that has been used to make significant contributions to research in hadronic physics. It connects the spin-dependent cross-section for photoproduction off a particle to the squared ratio of the particle's anomalous magnetic moment and its mass, $(κ / M)^{2}$ . Thus, for a nucleon embedded in a nucleus, the sum rule relates the cross-section to $κ / M$ averaged quadratically over the nucleons comprising the nucleus. This quadratic averaging can be used to constrain the mechanism responsible for the medium modification of the nucleon. We also point out that the global properties of the embedded nucleon like its axial charge, mass or magnetic moment are observables measurable through sum rules.
Comments:
8 pages, 1 figure
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2512.20449 [pdf]
PLB(2026)·1 citation
09
[Submitted on 23 Dec 2025]
Exploring quark mass dependent three-nucleon forces in medium-mass nuclei
Urban Vernik🇩🇪 · Kai Hebeler🇩🇪 · Achim Schwenk🇩🇪
Recently, new quark mass dependent three-nucleon (3N) forces have been identified, whose contributions in nuclear matter exceed expectations of Weinberg power-counting arguments. In this work, we investigate the impact of the most dominant new interaction term, characterized by the coupling $F_{2}$ , in ab initio calculations of medium-mass nuclei. For this, we combine the new $F_{2}$ interaction with established 3N interactions up to next-to-next-to-leading order (N $^{2}$ LO) and next-to-next-to-next-to-leading order (N $^{3}$ LO) in chiral effective field theory. We explore two fit strategies for the low-energy couplings. The first is based only on few-body observables, while the second also incorporates information from $^{16}$ O. Generally, we find that the $F_{2}$ interaction has a significant impact on energies and radii, however mainly due to changes in the short-range couplings. Overall, we do not find systematic improvements in the reproduction of medium-mass nuclei when the additional $F_{2}$ interaction is included.
Comments:
7 pages, 8 figures, minor changes and additions, published version
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2512.20454 [pdf]
PRC(2026)·2 citations
10
[Submitted on 22 Dec 2025] (cross-list from hep-ph)
CT25: Progress toward next-generation PDFs for precision phenomenology at the LHC
A. Ablat · A. Courtoy · S. Dulat · Y. Fu · M. Guzzi · T. J. Hobbs · J. Huston · K. Mohan · P. Nadolsky · M. Ponce-Chavez · D. Stump · K. Xie · C.-P. Yuan
We summarize recent progress toward the next generation of CTEQ-TEA parton distribution functions, CT25, based on a global NNLO analysis that incorporates a significant sample of newly included LHC data. We present a baseline fit within the forthcoming full CT25 fit, which includes new Drell-Yan, top-pair, and inclusive-jet data at 8 and 13 TeV, and exhibits non-trivial pulls on the high- $x$ gluon and the flavor structure of the quark sea. In the context of progress toward CT25, we also summarize several recent and ongoing studies of the interplay between phenomenological PDFs and lattice-QCD calculations, simultaneous extractions of $α_{s} (M_{Z})$ within the CT framework, and an expanded program of uncertainty quantification that treats parametrization dependence as an explicit source of epistemic uncertainty, among other issues. We also briefly highlight CT efforts to understand the effects of partial implementations of N $^{3}$ LO corrections into PDF fits, which include benchmark calculations for Higgs and vector-boson processes. We comment on the implications of recent improvements to the CT analysis for precision phenomenology at the LHC and future facilities.
Comments:
7 pages, 2 figures; talk presented at the XXXII International Workshop on Deep Inelastic Scattering and Related Subjects (DIS 2025), Cape Town, South Africa, 24-28 March 2025; minor textual clarifications in v2
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2512.19779 [pdf]
4 citations
11
[Submitted on 22 Dec 2025] (cross-list from astro-ph.HE)
Astrophysical constraints on the cold equation of state of the strongly interacting matter
Gábor Kasza🇭🇺 · János Takátsy🇭🇺 · György Wolf🇭🇺
At present, the only experimental access to the properties of cold, dense strongly interacting matter is provided by astrophysical observations. Neutron stars are the only known systems in the Universe that reach densities several times higher than normal nuclear density at nearly zero temperature, making them unique laboratories for studying dense matter. Since most neutron star observables are sensitive to the equation of state (EOS), observational data place stringent constraints on the EOS of strongly interacting matter. In this work, we investigate constraints arising from perturbative QCD calculations at asymptotically high densities ( $ρ \approx 40 ρ_{0}$ ), the mass of the heaviest observed neutron star (a black widow pulsar), NICER mass-radius measurements, and the tidal deformability inferred from the binary neutron star merger GW170817. We parametrize the EOS and allow its parameters to vary freely, using observational data to constrain the admissible parameter space. We find that neutron star observations significantly restrict the EOS of dense strongly interacting matter. While NICER has already provided measurements for five pulsars, the associated uncertainties remain relatively large. Within our modeling framework, we find that the existence of very massive neutron stars and constraints on the tidal deformability provide the most restrictive constraints on the EOS.
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2512.19907 [pdf]
Eur. Phys. J. Spec. Top. "High density nu…·2 citations
12
[Submitted on 23 Dec 2025] (cross-list from hep-ph)
Internal structure of near-threshold states using compositeness
Tomona Kinugawa🇯🇵 · Tetsuo Hyodo🇯🇵
Understanding the internal structure of near-threshold states is essential for revealing the nature of exotic hadrons. Motivated by this challenge, we discuss the clustering structures of near-threshold $s$ -wave eigenstates using the compositeness, which characterizes the clustering nature of the states. We show that shallow bound states usually possess cluster-dominant structures, while near-threshold narrow resonances are non-cluster-dominant. Through this study, we establish a theoretical foundation for the threshold energy rule, which has been known empirically.
Comments:
8 pages, 3 figures, Proceedings of Southeast Asian Workshop on Nuclear and Hadron Physics (SEA-NHP), August 19th - 21st, 2025
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2512.20155 [pdf]
0 citations
13
[Submitted on 23 Dec 2025] (cross-list from cond-mat.str-el)
Shear viscosity at finite magnetic field for graphene, non-relativistic and ultra-relativistic cases
Cho Win Aung · Thandar Zaw Win · Subhalaxmi Nayak · Sabyasachi Ghosh
The present article has addressed the finite magnetic field extension of the previous work by Cho et al. (Phys. Rev. B 108, 235172, 2023) on microscopic calculation of shear viscosity for electron fluid in graphene system. Our calculation is based on the kinetic theory approach in the relaxation time approximation. In the absence of a magnetic field, transport is governed by a single shear viscosity coefficient, whereas the application of a finite magnetic field induces anisotropy, giving rise to five independent shear viscosity coefficients associated with distinct velocity gradient tensors. These coefficients can be physically categorized into perpendicular, parallel, and Hall components relative to the magnetic field direction. When the scattering time equals the cyclotron time, the perpendicular component is suppressed by 80% and the parallel component by 50% and the Hall effect can reach maximum. Corresponding magnetic field strength for electron fluid in graphene is around 0.01-0.1 Tesla, and the same for non-relativistic electron fluid and ultra-relativistic quark fluid are around 10 Tesla and 10^{14} Tesla respectively. They may be considered as the required magnetic field strength in three different fluid systems to observe noticeable magnetic field response in their shear viscosity coefficients.
Comments:
13 pages, 4 Figures
Subjects:
Strongly Correlated Electrons (cond-mat.str-el); Nuclear Theory (nucl-th)
arXiv:
2512.20499 [pdf]
0 citations
14
[Submitted on 23 Dec 2025] (cross-list from hep-ph)
Inhomogeneous instabilities in high-density QCD
Jan M. Pawlowski🇩🇪 · Fabian Rennecke🇩🇪 · Franz R. Sattler🇩🇪
QCD at large densities exhibits a moat regime in the scalar-pseudoscalar sector. The resolution of its dynamics is pivotal for the access to the onset of new phases including the potential critical endpoint of QCD. In this work we present the first selfconsistent analysis of this regime with the functional renormalisation group approach to QCD. We map out the moat regime, including a first analysis of potential inhomogeneous instabilities at baryon chemical potential $μ_{B} ≳ 600$ MeV on the chiral crossover line.
Comments:
12 pages, 10 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2512.20510 [pdf]
19 citations
15
[Submitted on 23 Dec 2025] (cross-list from hep-ph)
A possible solution to the gallium anomaly moving beyond the leptonic wave function factorization
M. Cadeddu🇮🇹 · N. Cargioli🇮🇹 · F. Dordei🇮🇹 · L. Ferro🇮🇹 · C. Giunti🇮🇹 · M. Pitzalis🇮🇹
For over thirty years, a $\sim 20%$ deficit, now exceeding $5 σ$ , has persisted between measured and predicted neutrino capture rates on $^{71}$ Ga, as observed in radioactive source experiments (namely GALLEX, SAGE, and more recently BEST) using $^{51}$ Cr and $^{37}$ Ar. This long-standing discrepancy, referred to as the gallium anomaly, has posed a significant challenge to our understanding of both experimental methods and theoretical predictions. In this work, we revisit the theoretical calculation of the neutrino capture cross-section by moving beyond the standard treatment of the leptonic wave functions, revealing limitations in the commonly used factorization approach based on the detailed balance principle. Incorporating phenomenologically constrained Gamow-Teller transition densities, able to correctly reproduce the precisely measured half-life of $^{71} Ge$ , we find that the revised cross-section can be significantly reduced, potentially resolving the gallium anomaly without invoking new physics.
Comments:
7 pages, 1 figure; added compact transition-density solutions and expanded discussion of their nuclear-structure motivation
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2512.20560 [pdf]
3 citations

Affiliations

first authorsco-authorsvia INSPIRE