Nuclear Theory·nucl-th

Friday·November 14, 2025

11 papers—5 primary·6 cross-listed

01
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).
nucl-thnucl-exPRL(2026)·2 citations
02
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.
nucl-thhep-ph7 citations
03
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.
nucl-thhep-phnucl-ex5 citations
04
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.
nucl-thhep-phnucl-exPRC(2026)·2 citations
05
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.
nucl-th0 citations
06
The Non-thermal Energy Window for Laser-Driven Nuclear Reactions
Eunseok Hwang · Heamin Ko · Myung-Ki Cheoun · Dukjae Jang
Laser-driven nuclear reactions proceed in non-equilibrium plasma conditions, producing ion energy distributions that are not Maxwellian. Nevertheless, fusion yields in such experiments are often interpreted using effective thermal descriptions based on the conventional Gamow window. In this work, we develop an analytical framework for evaluating nuclear reaction rates for non-thermal ions accelerated by the Target Normal Sheath Acceleration (TNSA) mechanism. Using a self-similar plasma expansion model, we derive a closed form expression for an effective reaction energy window and the corresponding fusion reactivity. The resulting effective energies differ systematically from those predicted by thermal models, indicating limitations of interpretations based on the conventional Gamow window in laser-driven environments. This framework provides a quantitative basis for analyzing fusion yields and for designing laser-driven nuclear experiments.
↳ physics.plasm-phastro-ph.SRnucl-thNucl.Fusion(2026)·0 citations
07
Gauged Soft Recursion: On-Shell Construction of Goldstone-Gauge Amplitudes
Ian Low🇺🇸 · Ming-Lei Xiao🇨🇳 · Yu-Hui Zheng🇰🇷
We present a new on-shell recursion relation for scattering amplitudes involving Nambu-Goldstone bosons with a gauged unbroken symmetry. A central challenge is that gauge interactions break Adler's zero condition for charged scalars, invalidating the standard soft recursion. To overcome this, we introduce a ``gauged soft recursion'' that leverages the soft theorems of the gauge bosons themselves, combined with a novel decomposition of amplitudes into gauge-invariant components where Adler's zero is partially restored. The formalism, which also incorporates internal gauge bosons via angular momentum constraints, enables the systematic construction of tree-level amplitudes with arbitrary numbers of Goldstone bosons and gauge bosons in both Abelian and non-Abelian theories, as we demonstrate with explicit examples.
↳ hep-thhep-phnucl-thJHEP(2026)·1 citation
08
Geometry Induced Chiral Transport and Entanglement in $A d S_{2}$ Background
Kazuki Ikeda🇺🇸 · Yaron Oz🇮🇱
We study the real-time chiral dynamics of Dirac fermions in AdS $_{2}$ and AdS $_{2}$ black hole backgrounds. The spacetime curvature generates a spin connection term, acting as an effective magnetic field and a position-dependent chiral chemical potential. This leads to strongly asymmetric wave propagation, confined within an inhomogeneous Lieb-Robinson cone. The front velocities decrease with increasing fermion mass and horizon radius. The entanglement entropy grows inside the causal cone, and it saturates due to screening/dephasing in the finite inhomogeneous chain. In dipole-dipole collision, the central bipartite entropy rises when the inward Lieb-Robinson fronts intersect, forming a bright ridge in the local entanglement profile. Charge and current correlators peak at the front arrival, providing a real-time diagnostic of chiral transport. These results establish a causality-respecting framework, linking curvature and horizons to transport and entanglement in (1+1)-dimensional fermionic matter.
↳ hep-thcond-mat.mes-hallhep-phnucl-th+1JHEP(2026)·4 citations
09
CP violation
Alexey A Petrov🇺🇸
CP violation, which involves breaking the combined charge-conjugation (C) and parity (P) symmetries, is essential for understanding the observed matter-antimatter asymmetry in the universe. It is a key feature of the Standard Model, originating from complex phases in the Cabibbo-Kobayashi-Maskawa quark mixing matrix. Despite the successes of the SM, the amount of CP violation it predicts is not enough to explain baryogenesis, prompting searches for new sources of CP violation in other areas of particle physics. This article offers a pedagogical introduction to the theoretical foundations of C, P, and T symmetries and their combinations. It also emphasizes the importance of CP violation in modern particle physics and how it can be used to explore New Physics.
↳ hep-phhep-exnucl-th0 citations
10
Generalized Gross-Pitaevskii Equation for 2D Bosons with Attractive Interactions
Michał Suchorowski · Fabian Brauneis · Hans-Werner Hammer · Michał Tomza · Artem G. Volosniev
We introduce a generalized Gross-Pitaevskii equation that provides a nonlinear framework for studying two-dimensional (2D) attractive Bose systems. Its defining feature is the logarithmic density dependence of the coupling constant, which breaks the scale invariance inherent in the standard mean-field equations. This framework allows straightforward calculations of the system properties arising from the quantum anomaly. As a first illustration, we study universal bound states in free space, commonly referred to as quantum droplets. Then, we analyze breathing modes and quench dynamics in trapped systems, paving the way for a systematic exploration of non-equilibrium phenomena in 2D attractive Bose systems. Finally, we predict the existence of universal excited states, including vortex configurations, which may be more accessible to experimental investigation than the ground state. Our results provide a robust theoretical foundation for studying both static and dynamical properties of finite systems, and offer guidance for the design of future experiments.
↳ cond-mat.quant-gasnlin.PSnucl-thphysics.atm-clusPRL(2026)·0 citations
11
Possible $K K ˉ^{*}$ and $D D ˉ^{*}$ resonances by solving Schrödinger equation
Bao-Xi Sun · Qin-Qin Cao · Ying-Tai Sun
The one-pion exchange interaction between the kaon and the vector antikaon is investigated by solving the Schrödinger equation in the S-wave approximation. In addition to the particle $f_{1} (1285)$ , another bound state of $K K ˉ^{*}$ is obtained, which is approximately 9 MeV below the threshold of $K K ˉ^{*}$ and labeled $f_{1} (1378)$ for convenience in this manuscript. Under the outgoing wave condition, two resonance states of $K K ˉ^{*}$ are produced with different coupling constants fixed with the binding energies of $f_{1} (1285)$ and $f_{1} (1378)$ , respectively. Both of the resonance states are located in the vicinity of 1400 MeV, and thus it is reasonable to assume that these two resonance states correspond to the $f_{1} (1420)$ particle in the review of the Particle Data Group simultaneously. This method is extended to study the $D D ˉ^{*}$ system analogously. When the particle $χ_{c 1} (3872)$ is treated as a bound state of $D D ˉ^{*}$ , the particles $T_{c c ˉ 1} (3900)$ , $T_{c c ˉ} (4020)$ and $X (3940)$ can be obtained as solutions of the Schrödinger equation under the outgoing wave condition, which implies the spin and parity of these particles are all $J^{P} = 1^{+}$ .
↳ hep-phnucl-thPoS(2026)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE