Nuclear Theory·nucl-th

Friday·October 10, 2025

18 papers—12 primary·6 cross-listed

01
[Submitted on 8 Oct 2025]
A novel way of recasting the Bardeen-Cooper-Schrieffer gap equations
Georgios Palkanoglou · Alexandros Gezerlis
The gap equations lie at the core of the Bardeen-Cooper-Schrieffer (BCS) theory, a standard tool in the description of superfluidity. As a set of non-linear integral equations, the gap equations' inherent difficulties oftentimes hinder even the crudest descriptions of superfluid states. Hard-core potentials, high-density superfluids, and coupled-channel pairing are all reasons that have historically required one to provide special treatment to the gap equations to get a solution. In this paper we present a new method for solving the gap equations that holds the promise of being an efficient universal solver that requires the minimum amount of \textit{a priori} knowledge of the targeted solutions. With theoretical evidence of exotic nuclear superfluidity posing new questions to our understanding of this fundamental property of nuclear systems, the presented method can be a valuable tool when exploring new pairing states, finite-temperature properties, or the development of sophisticated descriptions of nuclear superfludity.
Comments:
12 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th); Superconductivity (cond-mat.supr-con)
arXiv:
2510.07384 [pdf]
PRC(2026)·0 citations
02
[Submitted on 9 Oct 2025]
Gamow shell model study of the 17Ne(p, p) reaction and of isospin symmetry breaking in 18Na
N. Chen · J. G. Li · K. H. Li · N. Michel · P. Y. Wang · W. Zuo
The unbound nucleus 18Na, acting as an intermediate nucleus in the sequential decay of 19Mg, is situated beyond the proton drip line. We employ the coupled-channel Gamow shell model (GSM-CC) to investigate the properties of 18Na, as well as the 17Ne(p, p) cross section. GSM-CC treats the nucleus as an open quantum system and provides a unified framework for studying both nuclear structure and reaction cross sections. Our calculations reproduce the energies and partial decay widths of low-lying states in 18Na, as well as the 17Ne(p, p) cross section. Additionally, the mirror nucleus 18N is also described. The isospin symmetry breaking induced by the Coulomb interaction and continuum coupling is clearly obtained in our description of 18Na and 18N properties, arising from the extended s1/2 partial wave. The isospin symmetry breaking in the 18Na/18N pair is compared to that occurring in the mirror pair 16F/16N, whereby similarities and differences are analyzed.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2510.07693 [pdf]
PRC·3 citations
03
[Submitted on 9 Oct 2025]
Gamow shell model calculations for the Thomas-Ehrman shift in new isotopes 21Al
K. H. Li · N. Chen · J. G. Li · H. H. Li · M. R. Xie · C. W. Ma · W. Zuo
Proton-rich nuclei beyond the proton drip line exhibit unique phenomena, such as the Thomas-Ehrman shift (TES), providing valuable insights into nuclear stability and isospin symmetry breaking. The discovery of the lightest new isotope, 21Al, situated beyond the proton drip line, was recently reported in the experiment. In this study, we employ the Gamow shell model (GSM) to explore the TES in mirror pairs 21Al/21O, focusing on how this phenomenon affects the energy levels of these nuclei. Our calculations describe the ground state energies and reveal significant TES with large mirror energy differences in the excited mirror 1/2+ states in 21Al/21O. The large mirror energy difference is primarily due to the significant occupation of weakly bound or unbound s1/2 orbitals, resulting in the extended radial density distributions, and variations in Coulomb energy and nuclear interaction contributions between the mirror states. Additionally, the low-lying states of 21Al are also calculated with the GSM in coupled-channel (GSM-CC) representation, Furthermore, we also predict the cross-section of 20Mg(p, p) scattering, which serves as another candidate approach to study the unbound structure of 21Al in the experiment, offering a theoretical framework for studying the structure and reaction dynamics of 21Al in future experiments.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2510.07701 [pdf]
PRC(2025)·5 citations
04
[Submitted on 9 Oct 2025]
Large scale shell model calculation for collectivity in nuclei beyond 78Ni
N. Chen · J. G. Li · H. H. Li
A shell model effective interaction for nuclei beyond the double magic nucleus 78Ni is constructed. First, the single-particle evolutions for valence neutrons above the double magic 78Ni are systematically explored in the N = 51 isotones using the large scale shell model (LSSM) calculations based on the constructed effective interaction. Subsequently, we calculate the excitation energies of 2+1 states and reduced electric quadrupole transition probabilities B(E2; 2+ to 0+) for N = 52 isotones. Notably, our calculation gives the result most consistent with the trend of the B(E2) values observed in the N = 52 isotones, especially for 84Ge, a result that poses a serious challenge to the theoretical model. Furthermore, the collectivity in N = 52 isotones, as well as the roles of pseudo-SU(3) symmetry, are investigated via the calculated primary configurations of their ground states and the first excited states. Additionally, the low-lying structures and band characteristics of neutron-rich Ge and Se isotopes are investigated. The ground state and the {\gamma}-soft band are constructed in our LSSM calculations, aligning well with available experimental evidence. Finally, we present the calculated evolutions of low-lying states in neutron-rich Ge and Se isotopes. The predictions for the as-yet unobserved low-lying states in these nuclei provide a comprehensive dataset to guide and inform future experimental efforts to decipher the evolution of shell structures and collectivity.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2510.07711 [pdf]
PRC(2024)·1 citation
05
[Submitted on 9 Oct 2025]
Probing the Neutron Skin with Extreme Collision Geometries in Heavy-Ion Collisions
Hui Zhang🇨🇳 · Alex Akridge🇺🇸 · Charles J. Horowitz🇺🇸 · Jinfeng Liao🇺🇸 · Hongxi Xing🇨🇳
Understanding how protons and neutrons are located differently in an atomic nucleus can provide fundamental information on nuclear structure and have far-reaching implications for astrophysics. A precise determination of this important difference, often quantified by the so-called neutron skin thickness, is challenging both theoretically and experimentally. Here we show how one can use a new category of observables in heavy ion collisions to probe the neutron skin thickness of nuclei like $^{208}$ Pb and $^{48}$ Ca, by utilizing the asymmetry between neutrons and protons of spectator nucleons in super-central collisions as well as that of participant nucleons in peripheral collisions. Using quantitative simulations, we demonstrate their sensitivity and great potential in constraining neutron skin thickness for both $^{208}$ Pb and $^{48}$ Ca nuclei in these extreme event geometries. Furthermore, we propose the asymmetric collisions between $^{48}$ Ca and $^{40}$ Ca nuclei as a unique and powerful way to nail down the neutron skin thickness.
Comments:
6 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2510.07816 [pdf]
4 citations
06
[Submitted on 9 Oct 2025]
Elliptic flow of deuterons from simulations with hybrid model
Tomas Polednicek🇸🇰 · Radka Vozabova🇸🇰 · Boris Tomasik🇸🇰
Elliptic flow of deuterons is measured on simulated collisions events of Pb+Pb at CMS energy of 2.76 TeV per colliding nucleon pair. We use hybrid model that includes hydrodynamics for the deconfined phase and hadron transport as an afterburner. For deuterons, two production mechanisms are examined: coalescence, and direct thermal production during hadronisation and subsequent transport through the hadronic phase. Differential elliptic flow of deuterons in different centrality bins is evaluated for both implemented production models. In this approach, coalescence describes the experimental data better than direct deuteron production.
Comments:
8 pages, 5 figures, version accepted in Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2510.07897 [pdf]
PRC(2026)·1 citation
07
[Submitted on 9 Oct 2025]
Collectivity and isomers in the Pb isotopes
Praveen C. Srivastava · Sakshi Shukla
In the present work, we aim to study collectivity in the Pb isotopes in the framework of nuclear shell model. We have performed shell-model calculations using KHH7B effective interaction. The model space of KHH7B interaction consists of 14 orbitals. We have reported results for even-even $^{196 - 206}$ Pb isotopes for spectra and electromagnetic properties. The shell model results for isomeric states are also reported. Our results will be useful to compare upcoming experimental data.
Comments:
11 pages, 5 figures, Interactions 245, 5 (2024)
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2510.08019 [pdf]
2 citations
08
[Submitted on 9 Oct 2025]
Determining the \Xi-Nucleus Potential from the Measured Binding Energies of ^15_\Xi^C
Paing Thit Nyein🇮🇳 · Kyaw Kyaw Naing🇮🇳 · Htun Htun Oo🇲🇲 · M. Yamaguchi🇯🇵 · Hiroyuki Kamada🇯🇵
The recent observation of the deeply bound \Xi - hypernucleus ^15_\Xi^-C through the IRRAWADDY and KINKA events provided a crucial benchmark for determining the \Xi-nucleus interaction. This work aims to constrain the depth of this potential by calculating the binding energy B_\Xi of the ^15_\Xi C system, which forms a \Xi^- -^14 N bound state. We achieve this by numerically solving the Schroedinger equation for a \Xi hyperon within a phenomenological Woods-Saxon potential, using the stable Numerov method, incorporating the Coulomb interaction. For a potential well depth V_0 = 12 MeV, our calculations yield a 0^+_1 state binding energy of 6.35 MeV and a 1^-_1 state energy of 0.87 MeV. These results are in excellent agreement with the IRRAWADDY event (B_\Xi = 6.27 \pm 0.27 MeV) and the shallower 1^-_1 states (KISO/IBUKI events, B_\Xi \approx 1 MeV), respectively. Assuming \Xi^0 instead of \Xi^-, we predict the ground state 0^+ of _{\Xi^0}^{15}N with (B_{\Xi^0} = 2.636 MeV) by omitting the Coulomb interaction as a first approximation.
Comments:
5page,no figure
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2510.08077 [pdf]
0 citations
09
[Submitted on 9 Oct 2025]
Probing Strange Dark Matter through $f$ -mode Oscillations of Neutron Stars with Hyperons and Quark Matter
Mahboubeh Shahrbaf🇵🇱 · Prashant Thakur🇰🇷 · Davood Rafiei Karkevandi🇵🇱
We investigate the impact of a hypothetical bosonic dark matter (DM) candidate, the sexaquark, on the fundamental ( $f$ -mode) oscillations of neutron stars (NSs). By varying the DM particle mass and considering different core compositions including hypernuclear matter, sexaquark DM, and deconfined quark matter (QM), we construct hybrid equations of state (EOS) with a smooth hadron--quark crossover that remain consistent with current astrophysical constraints on mass, radius, and tidal deformability. Our analysis shows that the presence of these exotic components systematically alters quasi-universal $f$ -mode relations. In particular, relations involving $f$ -- $M / R^{3}$ , $(R^{4} / M^{3} τ) (C)$ , $ω M (C)$ , require higher-order polynomial fits compared to standard studies. Quadratic forms remain sufficient for $f$ -- $M / R^{3}$ and $ω M (C)$ , while damping-time relations such as $(R^{4} / M^{3} τ) (C)$ demand higher-order corrections to capture their curvature. For $f (Λ)$ , a cubic fit provides a satisfactory description. Within this extended framework the relations remain tight and effectively composition independent. These results suggest that precise $f$ -mode measurements with future gravitational-wave detectors could provide clear signatures of DM and other exotic matter in NS interiors.
Comments:
Published as open access in JCAP
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2510.08115 [pdf]
JCAP(2026)·8 citations
10
[Submitted on 9 Oct 2025]
Charge state regulation of nuclear excitation by electron capture in $^{229}$ Th ions
Yang-Yang Xu · Qiong Xiao · Jun-Hao Cheng · Wen-Yu Zhang · Tong-Pu Yu
Nuclear excitation by electron capture (NEEC) in $^{229}$ Th holds significant potential for precise nuclear state manipulation. In this study, we thoroughly investigate NEEC in $^{229} Th^{q +}$ ions by integrating quantum numbers ( $n, l, j$ ) effects and analyzing key parameters (e.g., resonance energy $E_{r}$ , cross section $σ$ , resonance strength $S$ , and NEEC transition width $Γ_{NEEC}$ ) influences across charge state from $q = 1^{+}$ to $9 0^{+}$ . Especially, we focus on the charge-state regulation of the isomeric state (IS, 8.36 eV) and second-excited state (SE, 29.19 keV). Our calculations uncover critical charge-state-dependent behaviors of NEEC in $^{229} Th$ ions: (1) For the IS, valid NEEC channels exhibit threshold migration, where the dominant principal quantum number $n$ increases linearly with $q$ following the relation $n \approx 1.28 q + 4.23$ ; meanwhile, single- $n$ -channel $S$ stabilizes between $1 0^{- 2}$ to $1 0^{0}$ barn eV via compensatory nucleus-electron coupling, ensuring the total resonance $S$ constant. (2) For the SE, its excitation energy far exceeds nearly all electron binding energies, leading to negligible channel screening and causing the total $S$ to increase monotonically with $q$ . This research clarifies the intrinsic mechanisms of charge-state-driven nuclear-electronic interactions in $^{229} Th^{q +}$ NEEC and provides a critical reference for future experimental efforts to manipulate $^{229} Th$ nuclear states, particularly via indirect regulation of the SE.
Comments:
9 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2510.08212 [pdf]
Nucl.Sci.Tech.(2026)·5 citations
11
[Submitted on 9 Oct 2025]
On fluctuation properties of MACS
Milan Krticka · Aaron Couture
The Maxwellian Average Cross Section (MACS) is usually calculated with help of the statistical codes that do not take into account fluctuations of individual resonance parameters. The actual MACS can substantially deviate from its expectation value. This work focuses on description of various sources and aspects of these fluctuations. Simulated resonance sequences considering all the fluctuations involved in the statistical model are used for this purpose. Contribution of various sources of the fluctuations and neutrons with different orbital momenta are thoroughly investigated and described. Impact of available cross section data at low neutron energies is also checked. Based on this analysis simple empirical formulae for estimating relative fluctuations of MACS using solely $s$ -wave resonance spacing $D_{0}$ and the temperature of the stellar environment are derived. It is shown that real nuclei follow the proposed formula well. The expected MACS fluctuations increase with $D_{0}$ and can be significant. While for isotopes with $D_{0}$ in eV range the possible deviation from calculated values are small, for nuclei with $D_{0}$ in the keV range the full-width half-maximum of the expected distribution is larger than about 25\% and 10\% for astrophysically relevant temperatures of $k T = 8$ and 30 keV. At least for these nuclei the predictions from statistical codes must be taken with caution.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2510.08237 [pdf]
0 citations
12
[Submitted on 9 Oct 2025]
Hartree-Fock emulators for nuclei: Application to charge radii of $^{48, 52}$ Ca
Margarida Companys Franzke · Alexander Tichai · Kai Hebeler · Achim Schwenk
Understanding the emergence of complex structures of nuclei from chiral effective field theory (EFT) is a central challenge. The large number of low-energy couplings (LECs) in the EFT expansion and the significant cost of $ab initio$ many-body calculations render large-scale sensitivity studies of many-body observables computationally prohibitive, necessitating the use of emulators as low-cost surrogates. In this work, we study a Hartree-Fock emulator based on eigenvector continuation to investigate trends in nuclear charge radii of neutron-rich calcium isotopes. We systematically vary the five LECs entering the leading three-nucleon (3N) interactions, and demonstrate the precision of the emulator through cross-validation over a wide parameter space. Our findings indicate that large charge radius increase from $^{48}$ Ca to $^{52}$ Ca is likely not explained by variations of the leading 3N couplings. This suggests that other effects, such as sensitivities to chiral two-nucleon interactions or neglected many-body effects, e.g., associated with nuclear collectivity, play an important role.
Comments:
13 pages, 12 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2510.08362 [pdf]
PRC(2026)·7 citations

Affiliations

first authorsco-authorsvia INSPIRE