Nuclear Theory·nucl-th

Friday·September 4, 2026

11 papers—6 primary·5 cross-listed

01
[Submitted on 3 Sept 2026]
A Practical Partial-Wave Method for Identifying Unstable Light Nucleus Resonances in Heavy-Ion Collisions
Junlin Wu🇨🇳 · Hongchan Li🇨🇳 · Ke Mi🇨🇳 · Yaping Wang🇨🇳 · Guannan Xie🇨🇳
The production of light nuclei in relativistic heavy-ion collisions provides valuable insights into the dynamics of the hot and dense matter created in these extreme environments. While stable light nuclei have been extensively studied, unstable light nuclei being short-lived resonance states remain largely unexplored and offer unique opportunities to probe final-state interactions and the freeze-out conditions. In this paper, we propose a partial-wave method, based on the Lednický--Lyuboshitz framework, to extract resonance signals of unstable light nuclei from two-particle correlation functions measured in heavy-ion collisions. By extending the LL model to higher order partial waves and directly incorporating experimental phase-shift data from low-energy nuclear scattering, our approach avoids the need for model-dependent potential parametrizations and enables a clean decomposition of the resonant partial wave from the non-resonant background. As a demonstration, we apply the method to the $p$ - $^{3}$ He and $p$ - $^{4}$ He systems, corresponding to the $^{4}$ Li and $^{5}$ Li ground-state resonances. Numerical results show that the resonance-induced correlation excess can be effectively isolated, with a peak in the correlation function appearing at $k \approx 72$ MeV/ $c$ for $^{4}$ Li and $k \approx 50$ MeV/ $c$ for $^{5}$ Li, consistent with the known resonance parameters. The extracted transverse momentum spectra and rapidity distributions are presented using the measured proton and light-nuclei spectra from STAR at $s_{N N} = 3$ GeV. The proposed method provides a practical tool for the experimental study of unstable light nuclei in relativistic heavy-ion collisions and can be extended to a broader range of resonance states.
Comments:
25 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2609.03499 [pdf]
0 citations
02
[Submitted on 3 Sept 2026]
Influence of configuration-interaction on isospin impurities and isospin symmetry breaking corrections to superallowed $0^{+} \to 0^{+}$ beta decays
Jakub Wysocki🇵🇱 · Jan Miśkiewicz🇵🇱 · Jagjit Singh🇬🇧 · Wojciech Satuła🇵🇱
The symmetry-conserving density functional theory (DFT)-based no-core configuration-interaction (DFT-NCCI) framework is applied for the first time to investigate the impact of configuration interaction (CI) on the Coulomb (isospin) impurity, $α_{C}$ , in the ground and excited states of $^{10}$ C, $^{10}$ B, and $^{14}$ N, as well as on the isospin-symmetry-breaking (ISB) correction to the superallowed $0^{+} \to 0^{+}$ $β$ decay of $^{10}$ C. We demonstrate, among other findings, that within the DFT-NCCI framework CI has a negligible effect on the ground-state isospin impurities, which are dominated by a single doorway state. In contrast, CI significantly modifies the impurities in excited states, including the isobaric analogue $I = 0^{+}, T = 1$ state in $^{10}$ B. Hence, it also has a non-negligible impact on the ISB correction to the superallowed $β$ decay of $^{10}$ C. Our calculations yield $δ ˉ_{C} = 0.45 (4) %$ when the Coulomb interaction is taken as the sole source of ISB, and $δ ˉ_{ISB} = 0.46 (6) %$ when short-range charge-symmetry-breaking (CSB) terms are included in addition. Hence, no statistically significant dependence of the ISB correction on the short-range CSB interaction is observed for this decay. Comparison with our previous results reveals a strong sensitivity to the nuclear symmetry energy, which governs the strength of the isospin-restoring force and whose value in finite nuclei remains difficult to constrain because of its intricate dependence on the momentum-dependent terms of the effective interaction.
Comments:
12 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2609.03545 [pdf]
0 citations
03
[Submitted on 3 Sept 2026]
$α$ -decay for superheavy nucleus: The alpha decay energy to the one-fourth power
Jinyu Hu🇨🇳 · Chen Wu
Recently, Sobhani and Luo \cite{sobhani2025unified} proposed a new empirical formula for $α$ decay based on the $Q_{α}^{- 1/4}$ energy dependence, incorporating the proton number $Z$ , neutron number $N$ , and relative neutron excess $I = (N - Z) / (N + Z)$ as primary parameters. In this work, we extend this model by explicitly including the angular momentum of the emitted $α$ particle and the quadrupole deformation of the daughter nucleus. Using this improved formula to evaluate the $α$ -decay half-lives of 400 nuclei yields a root-mean-square (RMS) deviation of 0.97 relative to experimental data. Furthermore, we employ support vector regression (SVR)-taking $Q_{α}^{- 1/4}$ , $N$ , $Z$ , angular momentum, and daughter-nucleus deformation as input features-which further reduces the RMS deviation to 0.56. Finally, we apply both the extended formula and the SVR model to predict the $α$ -decay half-lives of even-even nuclei with $Z = 120$ and $Z = 122$ . The predicted half-lives show good consistency with those from the Sobhani and Poenaru formulas, and both approaches strongly support $N = 184$ as the next neutron magic number.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2609.03902 [pdf]
0 citations
04
[Submitted on 3 Sept 2026]
Reduced-basis method for linear response within nuclear density functional theory
Nobuo Hinohara · Xilin Zhang🇺🇸 · Jonathan Engel🇺🇸
Background: The quasiparticle random-phase approximation (QRPA) within nuclear density functional theory provides a powerful framework for describing collective excitations. Although the finite-amplitude method (FAM) efficiently solves the QRPA problem, repeated calculations for different external-field parameters remain computationally demanding. Purpose: We construct a reduced basis method (RBM)-based emulator for the FAM that treats the complex energy of the external field as a model parameter to efficiently reproduce FAM amplitudes and QRPA eigenmodes. Methods: High-fidelity FAM calculations are performed at a small set of training points in the complex-energy plane. The resulting FAM amplitudes form a non-orthogonal reduced basis. A variational equation yields an emulator that can predict the response at arbitrary complex energies and QRPA eigensolutions without additional full FAM calculations. Results: The RBM emulator accurately reproduces FAM strength distributions in both giant-resonance and low-energy regions when the relevant energy domain is covered by the training set. It also reproduces imaginary QRPA modes associated with shape instabilities of the HFB state. Applied to the $K^{π} = 0^{+}$ mode of rare-earth Dy isotopes in a realistic model space, the emulator reproduces strength distributions and the lowest $0^{+}$ collective states with precision comparable to full FAM calculations, reducing the computational cost by more than an order of magnitude. Conclusions: The RBM provides an efficient and accurate FAM emulator. Its ability to reproduce giant-resonance, low-energy, and imaginary-energy modes at drastically reduced computational cost makes it promising for density-functional optimization, calculations of collective inertia, and large-scale surveys of nuclear collective excitations.
Comments:
18 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2609.03903 [pdf]
0 citations
05
[Submitted on 3 Sept 2026]
Microscopic Calculation of Electric Quadrupole Effective Charges in Exotic Nuclei
Jia Liu · Yong Peng🇨🇳 · Xiao-Yan Zhu · Xiao-Hua Li🇨🇳 · Wen Luo · Yi-Fei Niu🇨🇳 · Wen-Hui Long
Electric quadrupole ( $E 2$ ) effective charges are evaluated based on the self-consistent relativistic Hartree-Fock single-particle states, with core-polarization corrections resummed to all orders using the Tamm-Dancoff approximation (TDA). Configuration-interaction relativistic Hartree-Fock (CI-RHF) calculations employing the TDA effective charges well reproduce the $B (E 2)$ strength for neon isotopes from stability to the neutron drip line. We find that polarization charges associated with continuum states are significantly quenched due to their extended density distributions and weak coupling to the core, underscoring the critical role of continuum effects in $E 2$ transition evaluations for exotic nuclei. Moreover, the CI-RHF model predicts a suppressed $B (E 2; 2_{2}^{+} \to 0_{2}^{+})$ in $^{30}$ Ne, together with strong in-band $B (E 2)$ strengths of the yrast band, suggesting the coexistence of a nearly spherical excited $0_{2}^{+}$ state and a deformed ground state within the $N = 20$ "island of inversion".
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2609.04044 [pdf]
0 citations
06
[Submitted on 3 Sept 2026]
B(E2) Serves as a Robust Signature of N = 32,34 Shell Evolution
Jia Liu · Yi Fei Niu🇨🇳 · Xiao Hua Lia · Wen Luo · Wen Hui Long
Electric quadrupole transition probabilities $B (E 2)$ serve as key probe of nuclear shell evolution, yet anomalous $B (E 2)$ values in exotic nuclei complicate the identification of new magic numbers. In this letter, employing the configuration-interaction relativistic Hartree-Fock model, we demonstrate that effective charges are sensitive to orbital radii, and this orbital dependence is significantly amplified by the halo structure of valence nucleons. This mechanism is critical for reliably describing $E 2$ transitions and understanding the unusual behavior of $B (E 2)$ in exotic nuclei. Our calculations predict reduced $B (E 2; 2_{1}^{+} \to 0_{1}^{+})$ values in $^{52, 54} Ca$ , signaling the emergence of subshell closures at $N = 32$ and 34. Furthermore, the suppressed $B (E 2; 7/ 2_{1}^{-} \to 11/ 2_{1}^{-})$ transition in $^{53} Sc$ underscores the robustness of the $N = 32$ new magic number, whereas the enhanced transition strength in $^{55} Sc$ indicates the rapid erosion of the $N = 34$ shell gap with the occupancy of the proton orbital $π 1 f_{7/2}$ .
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2609.04154 [pdf]
0 citations

Affiliations

first authorsco-authorsvia INSPIRE

A Practical Partial-Wave Method for Identifying Unstable Light Nucleus Resonances in Heavy-Ion Collisions

Influence of configuration-interaction on isospin impurities and isospin symmetry breaking corrections to superallowed 0+→0+ beta decays

α-decay for superheavy nucleus: The alpha decay energy to the one-fourth power

Reduced-basis method for linear response within nuclear density functional theory

Microscopic Calculation of Electric Quadrupole Effective Charges in Exotic Nuclei

B(E2) Serves as a Robust Signature of N = 32,34 Shell Evolution

Affiliations

Influence of configuration-interaction on isospin impurities and isospin symmetry breaking corrections to superallowed $0^{+} \to 0^{+}$ beta decays

$α$ -decay for superheavy nucleus: The alpha decay energy to the one-fourth power