Nuclear Theory·nucl-th

Tuesday·October 28, 2025

22 papers—12 primary·10 cross-listed

01
Enhancement of Alpha Decay due to Medium Effects
Pankaj Jain🇮🇳 · Harishyam Kumar🇮🇳
We study the effect of medium on radioactive alpha decay and other similar decays. The initial state in these type of decays is a quasi-bound state with energy greater than zero. Such a state has very large amplitude in the nuclear region and is exponentially suppressed at larger distances. The decay rate of such states is known to decrease rapidly with decrease in the Q-value. Here we study such a decay within a medium. We assume a simple spherically symmetric repulsive potential model for the medium. This models the cumulative effect of all nuclei in the medium which at short distances present repulsive Coulomb interaction. We find that as the Q-value becomes very small, the medium effects lead to a substantial enhancement in rate. In contrast, for large Q-values, the medium effects are negligible. We briefly comment on application to real systems and the experimental implications of this result.
nucl-th0 citations
02
Pairing gap as a new observable for critical points in the region of A=100
Hossein Emami · Hadi Sabri
This study used the pairing gap to identify nuclei as candidates for critical point symmetry around Z=40 and A=100. Nuclei around A = 100 display complex shape evolution and configuration crossing patterns. We utilized the experimental and algebraic frameworks of the interacting boson model and the newly developed interacting boson-fermion model to study the isotopes of Mo and Ru. The results show significant variations in these quantities across nuclei located at the E(5) and X(5) critical points, analyzed through different observables. We also examined another region that is suitable for a shape phase transition. Furthermore, our findings suggest new candidates for critical points in other phase transitional regions for different isotopic chains.
nucl-thnucl-exMod.Phys.Lett.A(2026)·0 citations
03
Origin of the electric hexadecapole isomer in $^{93}$ Mo
B. Maheshwari🇫🇷 · P. Van Isacker🇫🇷 · P. M. Walker🇬🇧
We present a shell-model analysis of $^{93}$ Mo to investigate the unusual behavior of its $21/2^{+}$ isomer -- a prominent candidate for nuclear excitation by electronic capture. This state is unique as its decay is dominated by a slow electric hexadecapole $E 4$ transition, while the typically much faster electric quadrupole $E 2$ decay path is energetically forbidden. We investigate the microscopic origin of this phenomenon by examining in detail the structure of the wave functions of the initial and final states, and the $E 4$ transition matrix elements. This analysis of $^{93}$ Mo is contrasted with that of its particle-hole conjugate, $^{99}$ Cd, where such an $E 4$ transition is absent.
nucl-thnucl-exEPJ Web Conf.(2025)·0 citations
04
Investigation of evaluated nuclear data in the prediction of inherent neutron sources
Sigtryggur Hauksson · Ilaria Casalbore · Daniele Tomatis · Nunzio Burgio
Quantifying inherent neutron sources in matter, particularly $(α, n)$ reactions and spontaneous fission, is important in nuclear engineering and other fields. The SOURCES code is a common tool for calculating the yield and spectrum of such neutrons. This paper critically examines all modelling assumptions and nuclear data in SOURCES and proposes alternative approaches where applicable. For $(α, n)$ reactions, we show that the alpha emission lines for $^{235} U$ should be updated. Furthermore, we compare four different stopping power data sets for alpha particles slowing down and propose measurements to constrain mixed oxide nuclear fuel data. We use the computer code PHITS to show that energy and angular straggling during the slowing down of alpha particles in the material of interest is unimportant. Then, we compare the cross section and emission spectrum of $(α, n)$ reactions in SOURCES to recently evaluated data libraries. Importantly, the modelling of SOURCES for the emission spectrum seems too simple and may need to be updated. Finally, we compare data on spontaneous fission and show that while the neutron yield from SOURCES is reliable, some discrepancy is found with the neutron spectrum of evaluated data libraries. Complementing this work is an implementation of spontaneous fission in the Monte Carlo code OpenMC.
nucl-thEur.Phys.J.Plus(2025)·0 citations
05
An End-to-End Generative Diffusion Model for Heavy-Ion Collisions
Jing-An Sun🇨🇳 · Li Yan🇨🇳 · Charles Gale🇨🇦 · Sangyong Jeon🇨🇦
Heavy-ion collision physics has entered the high precision era, demanding theoretical models capable of generating huge statistics to compare with experimental data. However, traditional hybrid models, which combine hydrodynamics and hadronic transport, are computationally intensive, creating a significant bottleneck. In this work, we introduce DiffHIC, an end-to-end generative diffusion model, to emulate ultra-relativistic heavy-ion collisions. The model takes initial entropy density profiles and transport coefficients as input and directly generates two-dimensional final-state particle spectra. Our results demonstrate that DiffHIC achieves a computational speedup of approximately $1 0^{5}$ against traditional simulations, while accurately reproducing a wide range of physical observables, including integrated and differential anisotropic flow, multi-particle correlations, and momentum fluctuations. This framework provides a powerful and efficient tool for phenomenological studies in the high-precision era of heavy-ion physics.
nucl-thnucl-exEPJ Web Conf.(2026)·0 citations
06
Non-local orbital-free density functional theory incorporating nuclear shell effects
Xinhui Wu · Gianluca Colò · Kouichi Hagino · Pengwei Zhao
Incorporating nuclear shell effects within the framework of orbital-free density functional theory (DFT) has remained a longstanding challenge in nuclear physics. While the Hohenberg-Kohn theorem formally guarantees the existence of an orbital-free density functional that is capable of describing all many-body effects, including shell effects, practical attempts since the 1970s have consistently failed to capture such effects. This persistent difficulty has even led to the misconception that the orbital-free DFT is inherently unable to describe nuclear shell effects. Here we develop a {\it non-local} orbital-free DFT approach for atomic nuclei and demonstrate that nuclear shell effects can be successfully incorporated into the orbital-free DFT through the construction of a non-local kinetic energy density functional. In particular, we show that the non-local orbital-free functional yields a nucleon localization function that, as an established indicator of shell effects, exhibits consistent behavior with the exact Kohn-Sham solution.
nucl-thnucl-exPRL(2026)·5 citations
07
Nucleon-nucleon scattering up to next-to-leading order in manifestly Lorentz-invariant chiral effective field theory: low phases and the deuteron
Xiu-Lei Ren🇨🇳 · E. Epelbaum🇩🇪 · J. Gegelia🇩🇪
Recently the nucleon-nucleon interaction derived using time-ordered perturbation theory in manifestly Lorentz-invariant chiral effective field theory was shown to yield promising results for peripheral neutron-proton scattering. In this work we study low partial waves at next-to-leading order by treating the potential non-perturbatively in the scattering equation. Reasonable description of the phase shifts in the $S$ and $P$ waves as well as the deuteron properties is observed, which can be regarded as a feasibility study for the application of our formalism to the few- and many-body calculations.
nucl-thPRC(2026)·2 citations
08
Baryon and electric charge stoppings in nuclear collisions and the role of strangeness
Mason Alexander Ross🇺🇸 · Zi-Wei Lin🇺🇸
It has been challenging to quantitatively understand the stopping of incoming nucleons in nuclear collisions, and recently it has been proposed that comparing the baryon stopping with electric charge stopping can help address the question. Here we focus on the $B / Q \times Z / A$ ratio, which can strongly depend on rapidity although its value is one for the full phase space. We find that this ratio is very sensitive to the difference between strange and anti-strange rapidity distributions (the $s - s ˉ$ asymmetry), and slightly more anti-strange quarks at mid-rapidity would lead to a ratio well below one. This is the case for Zr+Zr and Ru+Ru isobar collisions at $200 A$ GeV from a multi-phase transport (AMPT) model. Without the $s - s ˉ$ asymmetry, the AMPT model would give a mid-rapidity $B / Q \times Z / A$ ratio at or above one. In addition, the AMPT model gives $B /Δ Q \times Δ Z / A < 1$ at mid-rapidity for isobar collisions at all centralities, which strongly contradicts the recent data from the STAR Collaboration. We further find that the $B /Δ Q \times Δ Z / A$ ratio is very sensitive to the net-light quark ( $u, d$ ) stoppings, but it is less sensitive to the $s - s ˉ$ asymmetry than the $B / Q \times Z / A$ ratio by a factor of 3.
nucl-thhep-phnucl-exEPJC(2026)·4 citations
09
Calculation of Particle Pair Correlation Functions with Classical Trajectory Approximation
Sheng Xiao🇨🇳 · Yijie Wang🇨🇳 · Zhigang Xiao🇨🇳
Femtoscopic interferometry is a powerful tool for probing the spatio-temporal evolution of emission sources in heavy-ion collisions. A major challenge in the field is formulating a self-consistent description of the source function, final-state interactions between the particle pair, and interactions inherent to the source itself. To address this, we have developed a novel Monte Carlo model for calculating two-particle correlation functions in a classical trajectory approximation (CTA-I). The model incorporates self-consistently the emission source of thermal equilibrium and three-body final state interactions. Application of the model shows satisfactory fit to experimental data, revealing that the correlation function is highly sensitive to the source's spatio-temporal extent. In contrast, the temperature parameter governing the emitted particles' energy spectra has a negligible influence. Our approach offers the potential to extract the spatio-temporal information from the emission source, thereby advancing the applicability of femtoscopic interferometry in the Fermi energy domain.
nucl-thnucl-ex0 citations
10
Ground-state properties of finite nuclei in relativistic Hartree-Bogoliubov theory with an improved quark mass density-dependent model
Renli Xu · Chen Wu · Jian Liu · Bin Hong · Jie Peng · Xiong Li · Ruxian Zhu · Zhizhen Zhao · Zhongzhou Ren
A relativistic Hartree-Bogoliubov (RHB) model based on quark-meson coupling is developed, with a new parametrization derived from experimental observables. Using this model, we systematically investigate the ground-state properties of even-even nuclei spanning $8 \leq Z \leq 118$ , including binding energies, quadrupole deformations, root-mean-square (rms) charge radii, two-nucleon separation energies, two-nucleon shell gaps, and $α$ -decay energies. Comparisons with available experimental data demonstrate that this subnucleon-based RHB model reliably describes the ground-state properties of finite nuclei.
nucl-thCPC(2026)·0 citations
11
Multi-strange and charmed hadrons: A novel probe for the QCD equation of state at high baryon densities
Jan Steinheimer🇩🇪 · Tom Reichert🇩🇪 · Marcus Bleicher🇩🇪
Nuclear experiments near and below the threshold of hyperon production have shown that the production of Kaons is a sensitive probe for the dense QCD equation of state. At beam energies up to 1.5AGeV, strangeness production can probe the equation of state for densities up to approximately twice nuclear saturation. In this paper we will discuss the possibilities of extending this range in density by the study of multi-strange baryons as well as charmed hadrons in the SIS100 beam energy range up to $10 A$ GeV. Here, densities up to five times nuclear saturation can be reached and the production of multi-strange and charmed hadrons shows a strong sensitivity to the equation of state. On the other hand a precise prediction of the effect of the equation of state will require knowledge of the fundamental production cross section near the elementary production threshold in p+p collisions which is yet not measured for the hadrons discussed.
nucl-thhep-phEur.Phys.J.ST(2026)·4 citations
12
Observable Signatures of a Quarkyonic Phase in Neutron Stars
Probit J Kalita🇮🇳 · Tuhin Malik🇵🇹 · Tianqi Zhao🇺🇸 · Bharat Kumar🇮🇳 · James M. Lattimer🇺🇸
Quarkyonic matter in $\beta$-equilibrium is a potential description of cold dense matter in neutron stars (NSs), that introduces non-interacting quarks alongside nucleons and leptons in NS cores. In this paper, we impose observational and theoretical constraints on the model to perform Bayesian inference on it, and find that it is possible to have quarkyonic matter equations of state that satisfy all current astrophysical observations, thereby reinforcing the argument for its use alongside traditional ones. To differentiate between NSs where a quarkyonic phase does and does not appear in the core, we identify some novel signatures based on the mass-radius relation. Focusing on canonical ($1.4\ \mathrm{M_\odot}$) NSs, we find the populations of NSs with and without quarkyonic cores show separability on the basis of the slope and curvatures of the mass-radius curve, the central sound speed of the star, and the radius difference between two NSs of $2\ \mathrm{M_\odot}$ and $1.4\ \mathrm{M_\odot}$. Our results indicate that observing a neutron star with these signatures matching the values for quarkyonic core NSs would provide a strong evidence for the existence of a quarkyonic phase or a similar crossover transition in its core.
nucl-thastro-ph.HEgr-qc7 citations

Affiliations

first authorsco-authorsvia INSPIRE