Nuclear Theory·nucl-th

Friday·August 22, 2025

9 papers—6 primary·3 cross-listed

01
[Submitted on 20 Aug 2025]
Quantum Monte Carlo calculations in the nuclear shell model by the complex Langevin method
Yuhma Asano · Yuta Ito · Jun Nishimura · Noritaka Shimizu
The nuclear shell model is known to describe the properties of various nuclei extremely well. However, the auxiliary-field quantum Monte Carlo calculations cannot be applied to it with general interactions due to the sign problem. The model has therefore been investigated primarily by variational methods, where the accuracy of the results depends crucially on the ansatz for the wave function. Here we perform the auxiliary-field quantum Monte Carlo calculations in the case of small systems at finite temperature using the complex Langevin method (CLM), which has been successfully applied to various interesting systems with the sign problem over the decade. In particular, we show the existence of a parameter region in which the validity criterion for the CLM is satisfied and the expectation value of the energy obtained by exact diagonalization is correctly reproduced. Thus the CLM can be a complementary approach to the variational method for large systems.
Comments:
19 pages, 12 figures
Subjects:
Nuclear Theory (nucl-th); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th)
arXiv:
2508.15116 [pdf]
1 citation
02
[Submitted on 21 Aug 2025]
High-precision determination of radiative corrections to superallowed nuclear beta decays
Chien-Yeah Seng🇺🇸
Superallowed $0^{+} \to 0^{+}$ transitions between $T = 1$ nuclei have been a perfect avenue avenue for determining the Cabibbo-Kobayashi-Maskawa matrix element $V_{u d}$ , which imposes powerful constraints on physics beyond the Standard Model at low energies. For a long time, the precision of $V_{u d}$ has been limited by uncertainties in radiative corrections that arise from non-perturbative strong interaction physics at both the hadronic and nuclear levels. In this talk, I will describe some recent efforts to pin down these corrections by combining dispersive analysis with experimental data, lattice QCD, and nuclear many-body calculations.
Comments:
8 pages, 4 figures. Contribution to the Proceedings of the 14th International Spring Seminar on Nuclear Physics: "Cutting-edge developments in nuclear structure physics''
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2508.15203 [pdf]
EPJ Web Conf.(2025)·2 citations
03
[Submitted on 21 Aug 2025]
System-size dependence of $γ$ -jet modifications in heavy-ion collisions
Yu-Xin Xiao🇨🇳 · Qing-Fei Han🇨🇳 · He-Xia Zhang🇨🇳 · Hanzhong Zhang🇨🇳
Medium modifications of the $γ$ -triggered jets are investigated with the Linear Boltzmann Transport (LBT) model in heavy-ion collisions with varying system sizes, focusing on centrality dependence in Pb+Pb and Xe+Xe collisions at the LHC. Our numerical results reveal that jets produced in central collisions exhibit a wider transverse asymmetry ( $A_{N}^{y}$ ) distribution, a broader jet shape, and a more pronounced $γ$ -jet transverse momentum imbalance ( $X_{J γ} = p_{T}^{jet} / p_{T}^{γ}$ ) compared to peripheral collisions. These effects arise from the longer path length and stronger jet-medium interactions in central collisions, leading to enhanced jet quenching and medium response. Our findings demonstrate that the magnitude of $γ$ -jet modifications is sensitive to the size and centrality of the collision system, with larger systems inducing more significant alterations due to increased energy loss and medium feedback.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2508.15403 [pdf]
CPC(2025)·0 citations
04
[Submitted on 21 Aug 2025]
B(E2) anomaly and triaxial deformation within a two-fluid SU(3) symmetry
Wei Teng · Sheng Nan Wang · Yu Zhang · Xian Zhi Zhao · Xi Deng · Xiao Tong Li
The correlation between $B (E 2)$ structure and triaxial deformation has been investigated within the framework of the proton-neutron boson model. The analysis reveals that the distinctive feature, characterized by $B (E 2; 4_{1}^{+} \to 2_{1}^{+}) / B (E 2; 2_{1}^{+} \to 0_{1}^{+}) < 1.0$ along with $E (4_{1}^{+}) / E (2_{1}^{+}) > 2.0$ , can emerge from the triaxial SU(3) symmetry inherent in two-fluid boson systems, attributed to band-mixing effects. This suggests a symmetry-based understanding of the anomalous $E 2$ transitions observed in experiments.
Comments:
6 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2508.15414 [pdf]
CPC(2025)·7 citations
05
[Submitted on 21 Aug 2025]
Algebraic description of the triaxially to axially rotational shape phase transition
Yu Zhang · Yu Xin Liu · Feng Pan · J. P. Draayer
Within the framework of the interacting boson model, we propose a novel algebraic scheme to describe spin-dependent structural evolutions in triaxial nuclei. Our analysis demonstrates that a triaxially to axially rotational shape phase transition can be induced by the high-order correction which is microscopically motivated by the pairing interaction on the $γ$ -unstable rotation. This prescription is further applied to describe the structural evolutions along the yrast sequences of $^{132}$ Ba and $^{130}$ Xe, providing an exemplary case for demonstrating a unified explanation of both low-energy collective structures and high-spin phenomena in O(6)-like nuclei.
Comments:
11 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2508.15426 [pdf]
PRC(2025)·0 citations
06
[Submitted on 21 Aug 2025]
B(E2) anomaly and triaxial deformation in the interacting boson model
Yu Zhang · Wei Teng
The influences of triaxial dynamics on the anomalous $E 2$ transitional behaviors in the interacting boson model (IBM) have been comprehensively examined without symmetry restrictions. Specifically, different triaxial schemes in the IBM have been analyzed using a general procedure for deriving triaxial rotor modes based on two distinct approaches. The results indicate that the $B (E 2)$ anomaly feature, characterized by $B_{4/2} = B (E 2; 4_{1}^{+} \to 2_{1}^{+}) / B (E 2; 2_{1}^{+} \to 0_{1}^{+}) < 1.0$ , can occur in all triaxial schemes due to strong band-mixing effects. This finding is further tested in describing the available data for $^{172}$ Pt,~ $^{168, 170}$ Os and $^{166}$ W using the model constructed upon the extended consistent- $Q$ formula, providing a simple theoretical explanation of the depressed $B_{4/2}$ values observed in the experiments.
Comments:
14 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2508.15434 [pdf]
PRC(2025)·20 citations

Affiliations

first authorsco-authorsvia INSPIRE

Quantum Monte Carlo calculations in the nuclear shell model by the complex Langevin method

High-precision determination of radiative corrections to superallowed nuclear beta decays

System-size dependence of γ-jet modifications in heavy-ion collisions

B(E2) anomaly and triaxial deformation within a two-fluid SU(3) symmetry

Algebraic description of the triaxially to axially rotational shape phase transition

B(E2) anomaly and triaxial deformation in the interacting boson model

Affiliations

System-size dependence of $γ$ -jet modifications in heavy-ion collisions