Nuclear Theory·nucl-th

Monday·October 13, 2025

10 papers—7 primary·3 cross-listed

01
[Submitted on 9 Oct 2025]
Effect of Finite-Temperature $β$ -Decay Rates on the Rapid Neutron Capture Process
Yukiya Saito · Ante Ravlić · Pranav Nalamwar · Rebecca Surman
$β$ -decay is known to play an essential role in the rapid neutron capture process ( $r$ -process) during $(n, γ) \leftrightarrow (γ, n)$ equilibrium and freeze-out when the neutron-rich nuclei decay back to stability. Recent systematic theoretical studies on $β$ -decay at finite temperature indicated that under hot conditions ( $T \sim 10$ ~GK), a significant acceleration of $β$ -decay rates is expected, especially for nuclei near stability. This corresponds to the early stage of the $r$ -process. In this study, we investigate the effect of the $β$ -decays in finite temperature using the rates calculated with the finite-temperature proton-neutron relativistic quasiparticle random-phase approximation (FT-PNRQRPA). We explore a variety of astrophysical conditions and find that the effect on the abundance pattern is significant in hot and moderately neutron-rich conditions such as are expected in magnetorotational supernovae. Accelerated $β$ -decay rates also increase the heating rate in the early phase, resulting in an additional modification of the final abundance pattern.
Comments:
15 pages, 11 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2510.08772 [pdf]
ApJ(2026)·2 citations
02
[Submitted on 10 Oct 2025]
Thermal and Magnetic effects on Bulk Viscosity in Binary Neutron Star Mergers
Pranjal Tambe🇮🇳 · Debarati Chatterjee🇮🇳 · Mark Alford🇺🇸 · Alexander Haber🇬🇧
Astrophysical scenarios such as binary neutron star mergers, protoneutron stars, and core-collapse supernovae involve finite temperatures and strong magnetic fields. Previous studies on the effect of magnetic fields on flavor-equilibration processes relied on the Fermi surface approximation, which is not a reliable approximation in the neutrino-transparent regime of matter in supernovae or neutron star mergers. In a recent study, we went beyond the Fermi surface approximation, performing the full phase space integral to obtain direct Urca rates in a background magnetic field. In this work, we extend these calculations to incorporate the collisional broadening (modified Urca) contribution. We use the recently developed nucleon width approximation, which naturally includes the magnetic field dependence of all contributions. We demonstrate the impact of magnetic fields on the flavor-equilibrium condition for two finite-temperature equations of state with different direct Urca thresholds. We also study the impact of magnetic fields on the bulk viscous dissipation of density oscillations relevant in postmerger scenarios.
Comments:
Published in Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2510.09104 [pdf]
PRC(2026)·2 citations
03
[Submitted on 10 Oct 2025]
Indirect method for nuclear reactions and the role of the self energy
Gregory Potel
When a nuclear species (e.g., a nucleon or a deuteron nucleus) propagating freely is made to collide with a target nucleus, its trajectory is modified by exchanging variable amounts of energy, mass, linear and angular momentum with the target, according to its interaction with the nuclear medium. By addressing this perturbation away from the free path, one hopes to learn something about the nature of the medium through which our probe propagates. This is the essence of the experimental use of nuclear reactions for the purpose of gathering information about nuclear structure. In order to deal with the structure and the reaction aspects of a specific experiment on the same footing, it is therefore desirable to identify a theoretical construct that embodies the modification of the propagation of a particle in the medium with respect to the free case, and use it both for the determination of the nuclear spectrum (structure) and for the calculation of scattering observables (reaction). A candidate for such an object is the self energy, and we will try in the present lectures to put it at the center stage in the formulation of scattering theory.
Comments:
Contribution to the Proceedings of the International Summer School "Enrico Fermi", Course 213: Nuclear Structure and Reactions From a Broad Perspective, Varenna, Italy, June 27 - July 2, 2024
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2510.09140 [pdf]
0 citations
04
[Submitted on 10 Oct 2025]
Toroidal dipole mode in nuclei
Valentin Nesterenko · Petr Vishnevskiy · Anton Repko · Paul-Gerhard Reinhard · Jan Kvasil
A short review on the toroidal dipole mode (TDM) in nuclei is done. The appearance of TDM in nuclei is justified. The experimental manifestation of TDM in (e,e') reaction in 58Ni is shortly reported. The relation of TDM and pygmy E1 resonance is discussed.
Comments:
4 pages, 3 figures, contribution to proceedings of 29th International Nuclear Physics Conference (INPC-2025), May 25-30, 2025 (Daejeon, Korea)
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2510.09157 [pdf]
EPJ Web Conf.(2026)·0 citations
05
[Submitted on 10 Oct 2025]
Temperature dependence of the nucleon-nucleon inelastic cross section in an isospin-asymmetric nuclear medium
Manzi Nan🇨🇳 · Pengcheng Li🇨🇳 · Guojun Wei🇨🇳 · Xilong Xiang🇨🇳 · Wei Zuo🇨🇳 · Qingfeng Li🇨🇳
The nucleon-nucleon ( $N N$ ) inelastic cross section plays an important role in constraining the nuclear equation of state at high baryon density and in describing the formation and evolution of compact astrophysical objects. In this study, the temperature $T$ dependence of the $Δ^{++}$ and $Δ^{-}$ production cross sections in the isospin-symmetric and -asymmetric nuclear medium is investigated within the self-consistent and relativistic Boltzmann-Uehling-Uhlenbeck (RBUU) framework. Two relativistic mean-field parameterizations are employed: the density-dependent parameterization (called DD-ME $δ$ ) and the nonlinear-dependent parameterization (called OMEG). Both parameterizations yield similar $T$ -dependent baryon effective masses and mass splittings, although the OMEG set exhibits a stronger density dependence, particularly at higher densities ( $> 1.5 ρ_{0}$ ). Consequently, at lower densities, the energy, density, temperature, and isospin dependence of both $Δ^{++}$ and $Δ^{-}$ production cross sections are comparable for both sets, whereas at higher densities, the OMEG set predicts a stronger temperature and density sensitivity. Moreover, the $T$ dependence of the $N N$ inelastic cross section is enhanced with increasing density, but is suppressed in isospin-asymmetric nuclear matter compared to that in isospin-symmetric nuclear matter. The isospin dependence of the cross section remains nearly $T$ -independent at small asymmetries, yet becomes more intricate in highly asymmetric systems. These findings provide valuable testing inputs for improving the thermal treatment of $Δ$ related dynamical processes in transport models and offer insights into the behavior of $Δ$ in astrophysical environments, such as core-collapse supernovae and binary neutron star mergers.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2510.09337 [pdf]
1 citation
06
[Submitted on 10 Oct 2025]
Entanglement and accidental symmetries in the nucleon-nucleon system
Alma L. Cavallin🇸🇪 · Oliver Thim🇸🇪 · Christian Forssén🇸🇪
We study the connection between accidental symmetries in the nuclear interaction and spin entanglement in two-nucleon scattering. Specifically, we incorporate different levels of Wigner $S U (4)$ and Serber symmetries into leading-order potentials derived from chiral effective field theory. We conduct a quantitative analysis by computing the full $S$ matrix, demonstrating that the neutron-proton spin entanglement can be related to the symmetry properties of the interaction and the presence of certain operators and partial waves. Furthermore, we study the order-by-order evolution of the spin entanglement, up to next-to-next-to-leading order in Weinberg power counting, for both neutron-proton and neutron-neutron scattering. Entanglement suppression is not observed in neutron-neutron scattering, which can be attributed to the Pauli principle and the absence of accidental symmetries in this system. We conclude that entanglement is a useful guide for studying the power counting and symmetries in nuclear interactions derived from effective field theories.
Subjects:
Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2510.09466 [pdf]
PRC(2026)·10 citations
07
[Submitted on 10 Oct 2025]
Probing the Dependence of Partonic Energy Loss on the Initial Energy Density of the Quark Gluon Plasma
Ian Gill🇺🇸 · Ryan J. Hamilton🇺🇸 · Helen Caines🇺🇸
Considerable evidence now exists for partonic energy loss due to interaction with the hot, dense medium created in ultra-relativistic heavy-ion collisions. A primary signal of this energy loss is the suppression of high transverse momentum $p_{T}$ hadron yields in A-A collisions relative to appropriately scaled $pp$ collisions at the same energy. Measuring the collision energy dependence of this energy loss is vital to understanding the medium, but it is difficult to disentangle the medium-driven energy loss from the natural kinematic variance of the steeply-falling $p_{T}$ spectra across different $s_{NN}$ . To decouple these effects, we utilize a phenomenologically motivated spectrum shift model to estimate the average transverse momentum loss $Δ p_{T}$ imparted on high $p_{T}$ partons in A-A collisions, a proxy for the medium induced energy loss. We observe a striking correlation between $Δ p_{T}$ and Glauber-derived estimates of initial state energy density $ε_{Bj}$ , consistent across two orders of magnitude in collision energy for a variety of nuclear species. To access the path-length dependence of energy loss, we couple our model to geometric event shape estimates extracted from Glauber calculations to produce predictions for high- $p_{T}$ hadron elliptic flow $v_{2}$ that agree reasonably with data.
Comments:
16 pages, 11 figures, 3 tables (main body) + 5 pages, 2 figures, 2 tables (appendix). Total: 21 pages, 13 figures, 5 tables
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2510.09523 [pdf]
0 citations
08
[Submitted on 9 Oct 2025] (cross-list from hep-ph)
Exclusive photoproduction of light and heavy vector mesons: thresholds to very high energies
Lin Tang🇨🇳 · Hui-Yu Xing🇨🇳 · Minghui Ding🇨🇳 · Craig D. Roberts🇨🇳
A reaction model for $γ + p \to V + p$ , $V = ρ^{0}, ϕ, J / ψ, Υ$ , which exposes the quark-antiquark content of the photon in making the transition $γ \to q q ˉ + P \to V$ , where $q$ depends on $V$ , and couples the intermediate $q q ˉ$ system to the proton's valence quarks via Pomeron ( $P$ ) exchange, is used to deliver a unified description of available data -- both differential and total cross sections -- from near threshold to very high energies, $W$ , for all the $V$ -mesons. For the $Υ$ , this means $10 ≲ W / GeV ≲ 2000$ . Also provided are predictions for the power-law exponents that are empirically used to characterise the large- $W$ behaviour of the total cross sections and slope parameters characterising the near-threshold differential cross sections. Appealing to notions of vector meson dominance, the latter have been interpreted as vector-meson--proton scattering lengths. The body of results indicate that it is premature to link any $γ + p \to V + p$ data with, for instance, in-proton gluon distributions, the quantum chromodynamics trace anomaly, or pentaquark production. Further developments in reaction theory and higher precision data are required before the validity of any such links can be assessed.
Comments:
22 pages, 19 figures, 4 tables
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:
2510.08845 [pdf]
EPJC(2026)·10 citations
09
[Submitted on 10 Oct 2025] (cross-list from hep-ph)
Semihard interactions at TeV energies
T. V. Iser🇧🇷 · E. G. S. Luna🇧🇷
We investigate the high-energy behavior of the total cross section, $σ_{tot}$ , and the ratio of the real to imaginary parts of the scattering amplitude, $ρ$ , in both proton-proton and antiproton-proton channels. Our analysis is based on a QCD-inspired model in which the rise of the cross sections is predominantly driven by semihard processes involving gluons. We address the tension between measurements from the ATLAS/ALFA and TOTEM Collaborations, showing that independent analyses of their datasets can provide statistically consistent descriptions of the overall data, even though they do not fully reproduce the central values of the $ρ$ parameter at $s = 13$ TeV. The slight discrepancy between these central values and the model's predicted values, obtained using an asymptotic dominant crossing-even elastic scattering amplitude, points to the potential presence of an odd component in the semihard amplitude at high energies.
Comments:
9 pages, 2 figures, 2 tables; v2: minor revisions, correction of a typo in Eq. (19); version published in Phys. Rev. D
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2510.08963 [pdf]
PRD(2025)·0 citations
10
[Submitted on 10 Oct 2025] (cross-list from hep-lat)
Emergence of the $π (1300)$ Resonance from Lattice QCD
Haobo Yan🇨🇳 · Maxim Mai🇨🇭 · Marco Garofalo🇩🇪 · Yuchuan Feng🇺🇸 · Michael Döring🇺🇸 · Chuan Liu🇨🇳 · Liuming Liu🇨🇳 · Ulf-G. Meißner🇩🇪 · Carsten Urbach🇩🇪
The mass of the lightest hadron in nature, the pion, is one seventh of that of the nucleon and one tenth of the mass of its first excited state, the $π (1300)$ . This enormous energy difference opens an interesting window into the confinement of quarks and the structure of the lightest hadrons. In this Letter, we provide the first calculation of resonance parameters of the $π (1300)$ from lattice quantum chromodynamics (QCD). For this purpose, recently derived state-of-the-art tools are adapted and applied both in the construction of three-hadron operators and for mapping finite-volume spectra to infinite-volume amplitudes, subsequently analytically continuing these to complex energies. For our heavy pion mass ensembles, we find a clear signal of the resonance. Making a simple assumption of vanishing pion mass dependence for the three-body force, but incorporating constraints from Chiral Perturbation Theory for all the two-body channels, enables a robust extrapolation to the physical point. Applying model averaging, we extract a pole position of $M_{π (1300)} = (1169 \pm 46) - i (6 2_{- 62}^{+ 168}) \MeV$ supporting values from phenomenology.
Comments:
20 pages, 22 figures, 2 tables. v2: version published in PRL
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2510.09476 [pdf]
PRL(2026)·19 citations

Affiliations

first authorsco-authorsvia INSPIRE