Nuclear Theory·nucl-th

Friday·November 14, 2025

11 papers—5 primary·6 cross-listed

01
[Submitted on 13 Nov 2025]
Radii of proton emitters
Y. R. Lin🇨🇳 · S. M. Wang🇨🇳 · W. Nazarewicz🇺🇸
Nuclear radius is a fundamental structural observable that informs many properties of atomic nuclei and nuclear matter. Experimental studies of radii in drip line nuclei are in the forefront of research with radioactive ion beams. Of particular interest are charge radii of proton-unbound nuclei that will soon be approached in laser spectroscopy. In this Letter, using the complex-energy approach and direct time propagation, we investigate the radius of the proton resonance whose size is ill defined in the standard stationary quantum-mechanical description. An early-time plateau is identified during which the radius of the Gamow resonance coincides with the real-energy radius accessible experimentally. We demonstrate a nonmonotonic dependence of the complex radius on decay energy and a local increase of the charge radius across the threshold (a halolike enhancement).
Comments:
7 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2511.10238 [pdf]
PRL(2026)·2 citations
02
[Submitted on 13 Nov 2025]
Shedding Light on (Anti-)nuclei Production with Pion-Nucleus Femtoscopy
Li-Yuan Zhang🇨🇳 · Ze-Hua Zhang · Che Ming Ko🇺🇸 · Yu-Gang Ma🇨🇳 · Qi-Ye Shou🇨🇳 · Kai-Jia Sun🇨🇳 · Zhan-Duo Tang🇨🇳 · Rui Wang🇮🇹 · Song Zhang🇨🇳
High-energy nuclear collisions provide a unique environment for synthesizing both nuclei and antinuclei (such as $d ˉ$ and $^{4} He$ ) at temperatures ( $k_{B} T \sim 100$ MeV) much higher than their binding energies per nucleon of a few MeV. The underlying production mechanism, whether through statistical hadronization, nucleon coalescence, or dynamical regeneration and disintegration, remains unsettled. Here we address this question using pion-nucleus femtoscopy. By solving relativistic kinetic equations for pion-catalyzed reactions ( $π N N \leftrightarrow π d$ ) for deuteron production and including final-state $p -$ wave scatterings derived from an established effective interaction, we successfully reproduce the resonance peaks of both $π^{+} - p$ and $π^{+} - d$ femtoscopic correlations observed in $pp$ collisions at $s = 13 TeV$ . The interplay between $Δ$ resonance and $p$ -wave scatterings shifts both correlation peaks downward by about $70 MeV$ relative to vacuum $Δ$ decay. Conversely, both the nucleon coalescence model and the statistical hadronization model significantly underestimate the data and produce additional dips that are absent from the data. These results provide compelling evidence that pion-catalyzed reactions play a dominant role in the production of light (anti-)nuclei in high-energy nuclear collisions and cosmic rays.
Comments:
10 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2511.10298 [pdf]
7 citations
03
[Submitted on 13 Nov 2025]
Emulation of Proton-Deuteron Scattering via the Reduced Basis Method and Active Learning: Detailed Description
Alex Gnech🇺🇸 · Xilin Zhang🇺🇸 · Christian Drischler🇺🇸 · R. J. Furnstahl🇺🇸 · Alessandro Grassi🇮🇹 · Alejandro Kievsky🇮🇹 · Laura E. Marcucci🇮🇹 · Michele Viviani🇮🇹
Nucleon-deuteron ( $N d$ ) scattering can be used to constrain three-nucleon forces in chiral effective field theory ( $χ$ EFT). However, high-fidelity calculations, such as the Hyperspherical Harmonic (HH) method, are computationally expensive, making it difficult or even prohibitive to explore the vast parameter space of $χ$ EFT\xspace. To address this challenge, specifically for proton-deuteron ( $p d$ ) scattering below the deuteron breakup threshold, we developed model-driven emulators based on the Reduced Basis Method (RBM) and active learning techniques, as presented in \href{https://arxiv.org/abs/2511.01844}{arXiv:2511.01844}. The method exploits the similarities between solutions at different parameter points to significantly reduce computational costs. In this companion paper, we provide a comprehensive description of our HH-based high-fidelity calculations and implementation of both variational-method-based and Galerkin-projection-based scattering emulators. We demonstrate the effectiveness of active learning in the form of greedy algorithms for selecting optimal training points in the parameter space, and the high accuracy and speed of the emulators, for two different nucleon forces and two scattering channels ( $1/2^{+}$ and $1/2^{-}$ ). For example, in a two-dimensional parameter space, the relative emulation errors can be reduced to $1 0^{- 7}$ with fewer than 10 training points. Our work paves the way for the efficient calibration of $χ$ EFT\xspace nucleon interactions using Bayesian statistics, and the methodology can be applied to other nuclear scattering processes (including neutron-deuteron scattering), as well as other finite quantum systems.
Comments:
24 page, 16 figures, 1 table
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2511.10420 [pdf]
5 citations
04
[Submitted on 13 Nov 2025]
Friction terms in multi-fluid description of heavy-ion collisions
Clemens Werthmann🇧🇪 · Iurii Karpenko🇨🇿 · Pasi Huovinen🇵🇱
In multi-fluid description of heavy-ion collisions, the primary scatterings and particle production are described in terms of interaction between fluids, so called friction. These friction terms can be derived from kinetic theory, but they are not unique. We compare different approaches to derive the friction terms, introduce a new ``charge transfer" friction, which allows to move charge to the midrapidity fireball, and implement them in the MUFFIN model. The charge transfer friction is more consistent with the assumption of three fluids clearly separated in momentum space, and allows better comparisons of the experimental data and underlying equation of state. It also leaves room for entropy generation due to dissipation in individual fluids, and we present the first results obtained using viscous multi-fluid dynamics.
Comments:
14 pages, 6 figures. v2: Minor changes, equivalent to published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2511.10487 [pdf]
PRC(2026)·2 citations
05
[Submitted on 13 Nov 2025]
Non-Resonant Alpha-Induced Neutron-Emission: A Multi- Method Comparison Of Nuclear Reaction Rates
Bhavay Luthra · N. J. Upadhyay
The precise calculation of alpha-induced neutron-emission ( $α$ ,n) reaction rates is fundamental to understanding nucleosynthesis in diverse stellar environments. This study investigates the nuclear reaction rates for various non-resonant alpha-induced neutron-emission reactions by employing analytical, theoretical, and computational methods. We have adopted analytical expressions from existing literature, and for the computational approach, we have implemented the Monte Carlo method. To better understand the functionality and validate the established open-source Monte Carlo scripts, we also developed our own computational code and used it to test various aspects of the method. A comprehensive comparison of the reaction rates from each method is presented by plotting their dependency on temperature.
Comments:
7 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2511.10536 [pdf]
0 citations

Affiliations

first authorsco-authorsvia INSPIRE

Radii of proton emitters

Shedding Light on (Anti-)nuclei Production with Pion-Nucleus Femtoscopy

Emulation of Proton-Deuteron Scattering via the Reduced Basis Method and Active Learning: Detailed Description

Friction terms in multi-fluid description of heavy-ion collisions

Non-Resonant Alpha-Induced Neutron-Emission: A Multi- Method Comparison Of Nuclear Reaction Rates

Affiliations