Nuclear Theory·nucl-th

Tuesday·March 10, 2026

25 papers—17 primary·8 cross-listed

01
[Submitted on 7 Mar 2026]
Ab initio study of the halo structure in $^{11}$ Be
Shihang Shen · Serdar Elhatisari · Dean Lee · Ulf-G. Meißner · Zhengxue Ren
We present an ab initio study of the one-neutron halo nucleus $^{11}$ Be using nuclear lattice effective field theory with high-fidelity chiral interactions at N3LO. By employing the wavefunction matching method to mitigate the sign problem and the pinhole algorithm to sample many-body correlations, we successfully reproduce the ground-state parity inversion and the extended matter radius characteristic of the halo structure. We analyze the intrinsic density distributions and geometric shapes of $^{11}$ Be in comparison with the core nucleus $^{10}$ Be. Our results reveal a prominent two-cluster structure in both nuclei and the occupation of the $σ$ molecular orbital by the valence neutron in $^{11}$ Be. It enhances the prolate deformation as well as the diffuse neutron tail, distinct from the $π$ -orbital occupation observed in the $^{10}$ Be ground state.
Comments:
Selected Papers from the International Symposium Commemorating the 40th Anniversary of Halo Nuclei; 9 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.06978 [pdf]
Particles(2026)·5 citations
02
[Submitted on 7 Mar 2026]
Combined Garvey Kelson Relations for Mass Determinations and Machine Learning
I. Bentley · A. Fiorito III · M. Gebran · W. S. Porter · A. Aprahamian
Simple Garvey Kelson mass relations applied in two regions are often used as an evaluation metric for machine learning based mass models. These relations have also been used in the training of some machine learning based models. Unfortunately, these Garvey Kelson relations do not broadly sum to zero as is sometimes assumed. In this manuscript, we generate three Garvey Kelson based mass relations that have been optimized with the goal of predicting nuclear masses the most accurately. These three relations have each been optimized for specific tasks. One relation has been optimized to predict the masses on the corner of a 5-by-5 grid. One has been optimized to predict the central mass on that grid, and the last has been optimized to work over the entire grid. Using these relations with the AME 2020 N & Z > 7 data, the central nucleus can be determined with a 129 keV standard deviation, any of the four corner masses with a 472 keV standard deviation, and the overall measure finds a 35 keV standard deviation for a per difference metric. We have compared these results with those from theoretical mass models and have tested the prediction and extrapolation capabilities of the relation that predicts corner masses. We also discuss how these relations can be implemented in machine learning based approaches.
Comments:
Version 1, submitted to Physical Review C
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.07015 [pdf]
0 citations
03
[Submitted on 7 Mar 2026]
$^{14}$ N(p, $γ)^{15}$ O $S$ factor and the puzzling solar composition problem
G.X. Dong🇨🇳 · X.B. Wang🇨🇳 · N. Michel🇨🇳 · M. Płoszajczak🇫🇷
In stellar hydrogen burning, the CNO cycle dominates, with the $^{14}$ N(p, $γ)^{15}$ O reaction being the slowest process. Consequently, this reaction critically influences the solar composition, CNO neutrino fluxes, and the evolution of star clusters and galaxies. Recent direct measurements of $^{14}$ N(p, $γ)^{15}$ O have reported an enhanced astrophysical $S$ -factor. This work presents a microscopic theoretical study of the $^{14}$ N(p, $γ)^{15}$ O reaction using the Gamow shell model in the coupled-channel representation (GSM-CC). The calculations achieve good agreement with experimental data for both the total $S$ -factors and the separate contributions from transitions to the ground state and excited states of $^{15} O$ . However, the predicted $S$ -factor at zero energy exceeds the experimental value. Based on the computed $S$ -factors, the derived carbon and nitrogen abundances align closely with predictions from recent $^{14}$ N(p, $γ)^{15}$ O cross-section measurements, yet remain significantly lower than the latest solar neutrino observation values.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.07056 [pdf]
PRC(2026)·0 citations
04
[Submitted on 7 Mar 2026]
$β$ -Decay Half-Lives Serve as Novel Evidence for the New Magic Number $N=32$
L. Guo · Z. H. Wang · X. L. Zhi · Y. F. Niu · W. H. Long · Z. M. Niu · Q. B. Zeng · Z. Liu
Conventional signatures of nuclear magic number, including low-lying quadrupole collectivity and mass systematics, face significant challenges when probing emergent shell closures near the drip line. However, $β$ -decay half-lives are among the first experimental observables measurable following the discovery of neutron-rich isotopes. This letter demonstrates that $β$ -decay half-lives provide evidence for the emergent magic number $N = 32$ . The observed half-life pattern around the $N = 32$ can be attributed to the occupation probabilities of orbitals above this shell gap, which directly reflect the gap's magnitude. Our results reveal a pronounced $N = 32$ shell gap in Ca isotopes and a weaker yet apparent gap in K isotopes, consistent with mass and electromagnetic transition data. Furthermore, the analysis indicates no prominent closed-shell signature at $N = 32$ in Ar and Cl isotopes.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2603.07069 [pdf]
0 citations
05
[Submitted on 7 Mar 2026]
Microscopic investigation of $γ$ vibrational band structures in odd-mass nuclei
Uzma Jahangir · S. P. Rouoof · S. Jehangir · G. H. Bhat · J. A. Sheikh · N. A. Rather
A systematic investigation of the high-spin band structures observed in $^{103, 105, 107, 109}$ Nb and $^{103, 105, 107, 109}$ Tc nuclides is performed using the triaxial projected shell model (TPSM) approach. For $^{103, 105}$ Nb isotopes, four bands have been populated with the lowest three bands corresponding to yrast, $γ$ and 2 $γ$ bands. The nature of the fourth observed band has remained unresolved as it has been shown from the transition intensity ratios that this band cannot correspond to the expected 3 $γ$ band. It is demonstrated in the present work that this fourth band is the second $γ$ band, resulting from the combination, $K = K_{0} - 2$ with $K_{0}$ being the " $K$ " value of the parent configuration. The excitation energy and other properties of this band structure are predicted for all the studied nuclides.
Comments:
11 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.07157 [pdf]
PRC(2026)·0 citations
06
[Submitted on 7 Mar 2026]
Collective Flow, Kinetic Freeze-Out, and a Data-Driven Baryon Chemical Potential in Au+Au Collisions at $s_{N N} = 7.7$ -- $39$ GeV
Sk Noor Alam · Victor Roy
We study how transverse and longitudinal collective flow affect kinetic freeze-out conditions and the net baryon density in 0--5\% central Au+Au collisions at $s_{N N} = 7.7$ -- $39$ GeV, using a covariant statistical fireball model fitted to STAR identified-hadron transverse-momentum spectra at three fixed longitudinal velocities $v_{z} = 0$ , $0.2$ , and $0.4$ . \rev{Longitudinal flow shifts the extracted temperature upward through a kinematic $v_{z}$ -- $T$ degeneracy rather than by hardening the spectra; imposing $T \leq T_{c} \approx 155$ -- $160$ MeV bounds the longitudinal flow to $v_{z} ≲ 0.6$ .} \nw{A simultaneous $π^{+}$ , $K^{+}$ , $p$ fit with shared $(T, v_{T})$ sharpens the extraction \fx{by a factor of $3.7$ -- $5.3$ on $T$ relative to the single-species proton fit} and gives $T_{kin} ≃ 107$ -- $115$ ~MeV, reproducing STAR's independent blast-wave values \fx{to within $0.9 σ$ } and lying well below the chemical freeze-out temperature.} \fx{Further including the antiproton spectra, with a normalization shared between $p$ and $p ˉ$ , breaks the fugacity--normalization degeneracy and makes the baryon chemical potential data-driven: the $p ˉ / p$ ratio fixes $μ_{B} / T$ , the meson spectra fix $T$ , and together they give $μ_{B} ≃ 262$ -- $63$ ~MeV at kinetic freeze-out, satisfying $μ_{B} / T_{kin} ≃ (0.85$ -- $0.88) μ_{B}^{ch} / T_{ch}$ : the $p ˉ / p$ ratio is thus largely, but not exactly, set at the chemical surface, the $12$ -- $15%$ deficit being significant at up to $3.2 σ$ . The resulting kinetic freeze-out trajectory in the $(ρ_{B}, ε)$ plane shows that decoupling occurs in a dilute system, reaching only $ρ_{B} ≃ 0.03 n_{0}$ at $7.7$ ~GeV, \fx{a factor of $≃ 25$ } below the chemical-surface compression maximum, while longitudinal flow raises the inferred \fx{ $ρ_{B}$ } by up to a factor of $\sim$ 4.}
Comments:
We added few figures and changed the text . 19 pages with 14 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.07160 [pdf]
1 citation
07
[Submitted on 7 Mar 2026]
Shape phase transition, coexistence and mixing in the $^{98 - 106}$ Ru isotopes
R. Budaca · P. Buganu · F. El Ouardi · A. Lahbas
The deformation properties within the $^{98 - 106}$ Ru even-even isotopic chain, are investigated by means of the Covariant Density Functional Theory with a Density-Dependent Point-Coupling X parametrization. The considered nuclei are found to exhibit very shallow prolate and triaxial ground state deformation. This information is used to ascertain their dynamical behavior within prolate $γ$ -stable and $γ$ -unstable instances of a phenomenological Bohr-Mottelson Hamiltonian with an octic potential in the axial deformation variable. The comparative study of the low-lying collective states, revealed the presence of a shape phase transition from low to high deformation, as well as evidence of shape coexistence and mixing between spherical vibrator, $γ$ -unstable or prolate configurations in ground and excited states. It is also shown that the effect of shape coexistence and mixing on the $γ$ -band states can account to some extent for the typical $γ$ -unstable staggering even in prolate $γ$ -stable conditions.
Comments:
26 pages, 23 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.07194 [pdf]
PRC(2026)·2 citations
08
[Submitted on 7 Mar 2026]
Ab initio mapping of the boundary of the $N = 20$ island of inversion
E. F. Zhou · C. R. Ding · Q. Y. Luo · J. M. Yao · H. Hergert
Starting from a chiral two- plus three-nucleon interaction, we perform a systematic study of the low-lying states of neutron-rich nuclei around $N = 20$ using the in-medium generator coordinate method (IM-GCM), which combines the multi-reference in-medium similarity renormalization group (MR-IMSRG) with the quantum-number projected generator coordinate method (PGCM) defined in a full single-particle space. The main features of the energy spectra and electromagnetic properties of low-lying states in both even-even and odd-mass nuclei of this mass region are reasonably reproduced. The boundary of the $N = 20$ island of inversion (IOI) is investigated, and the results indicate that $^{30}$ Ne, $^{29, 31, 33}$ Na, $^{31 - 34}$ Mg, and $^{35}$ Al lie within the IOI, whereas $^{29}$ F, $^{29}$ Ne, $^{30}$ Mg, $^{31, 33}$ Al, $^{34, 35}$ Si, and $^{35}$ P fall outside it.
Comments:
17 pages with 15 figures and 1 table
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2603.07363 [pdf]
Phys. Rev. C (2026)·3 citations
09
[Submitted on 8 Mar 2026]
Nuclear Deformation Effects on Charmonium Suppression in Au+Au and U+U Collisions
Jiamin Liu🇨🇳 · Huanshang Yang🇺🇸 · Baoyi Chen🇨🇳
We investigate the impact of intrinsic nuclear deformation and orientation on the yield suppression and momentum anisotropy of charmonia in Au+Au and U+U collisions at the Relativistic Heavy-Ion Collider. The anisotropic nucleon density within the nucleus is parameterized using a modified Woods-Saxon distribution, which is incorporated into the initial distributions of both the heavy quarkonia and the bulk medium energy density. The well-established Boltzmann-type transport equation is utilized to describe the dynamical evolution of quarkonium in the anisotropic bulk medium. Treating quarkonium suppression in Au+Au collisions as a baseline, we find that the momentum-integrated charmonium yield suppression is relatively insensitive to the initial nuclear geometry in deformed U+U collisions. In contrast, the anisotropic flow coefficients ( $v_{n}$ ) of the charmonium is more sensitive to the nuclear deformation. Furthermore, these observables are also connected with the collision configuration, particularly when distinguishing between tip-tip and body-body orientations in U+U collisions at $s_{N N} = 193$ GeV. This effect is more pronounced for the excited state due to its smaller binding energy and heightened sensitivity to the initial energy density of the hot QCD medium.
Comments:
8 pages, 22 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2603.07547 [pdf]
PRC(2026)·0 citations
10
[Submitted on 8 Mar 2026]
Prolate-oblate shape competition and impact on charge radii in Bk isotopes
Ting-Ting Sun · Qi Zhang · Peng Wang · Zi-Dan Huang · Shuang-Quan Zhang
The nuclear charge radius provides a fundamental probe of nuclear structure, yet experimental data remain rare in the actinide region. Using the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) with the PC-PK1 functional, we carry out a systematic investigation of prolate-oblate shape competition in odd- $A$ Bk isotopes. Deformation is found to play an important role in the description of charge radii $r_{c}$ by extending the density distribution. Notably, $r_{c}$ exhibits a distinct shape dependence: for a given absolute quadrupole deformation $∣ β_{2} ∣$ , oblate shapes yield larger charge radii than their prolate counterparts in well-deformed nuclei near the mid-shell region, where the empirical formula $r_{c} (β_{2}) = (1 + \frac{5}{4 π} ∣ β_{2} ∣^{2}) r_{c} (0)$ fails to capture the observed behavior. This enhancement is attributed to a central depression (or ``bubble" structure) in the proton density, which microscopically originates from the non-occupation of the spherical $3 s_{1/2}$ ( $Ω = 1/2$ ) orbital in oblate minima. These findings establish a clear microscopic connection between nuclear shape, single-particle occupancy, and nuclear size.
Comments:
9 pages, 5 figures, 1 table
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.07596 [pdf]
0 citations
11
[Submitted on 8 Mar 2026]
Constraining the neutron skin of $^{208}$ Pb with anisotropic flow in Pb+Pb collisions at the LHC
Xin-Li Zhao🇨🇳 · Xin-Yi Xie🇨🇳 · Yuan Li🇨🇳 · Guo-Liang Ma🇨🇳
We study neutron-skin effects of $^{208}$ Pb in Pb+Pb collisions at $s_{NN} = 5.02$ ~TeV using the improved string-melting version of a multi-phase transport model by varying the neutron density distribution. A systematic response is observed in both the initial eccentricities and the anisotropic flow, indicating that neutron-skin effects survive the full transport evolution of heavy-ion collisions. A $χ^{2}$ comparison with ALICE data favors small to moderate neutron skin, while large neutron skin is excluded. The similar descriptions provided by zero and moderate neutron skin point to a geometric degeneracy in the current anisotropic flow in Pb+Pb collisions, where anisotropic flow is primarily driven by the overall collision geometry and size, thus lacking extreme sensitivity to the fine details of the nuclear surface profile. This highlights both sensitivity and limitation of constraining neutron-skin properties with flow measurements in Pb+Pb collisions at the LHC.
Comments:
8 pages, 8figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2603.07597 [pdf]
2 citations
12
[Submitted on 9 Mar 2026]
Centrifugal-corrected harmonic oscillator model for spherical proton emitters
Xiao-Yan Zhu · Wei Gao · Jia Liu · Li-Qiang Zhu · Wen-Bin Lin · Xiao-Hua Li
In the present work, we propose an improved harmonic oscillator model to systematically evaluate the proton radioactivity half-lives in spherical nuclei, incorporating centrifugal potential effects. By fitting the experimental data, the centrifugal parameter $d = 0.143$ for the correction term $d l (l + 1)$ and nuclear potential depth $V_{0} = 62.4$ MeV are obtained. The model integrates the relativistic mean field (RMF) theory with the BCS method based on the DD-ME2 force to determine spectroscopic factors $S_{p}$ . Moreover, by verifying the linear relationship between the logarithm of the normalized width $lo g_{10} γ^{2}$ and fragmentation potential $V_{f r a g}$ , the connection between nuclear structure and tunneling dynamics is confirmed, and an analytical expression for the adjustable parameter $d$ corresponding to the centrifugal potential is derived as $d^{Ae}$ $\approx$ 0.167. Compared with $d^{Ae}$ , the modified model based on $d$ yields results in better agreement with experimental half-lives, and is able to control the error of the experimental data within a factor of 2.4. Furthermore, the extended improved model is used to predict the half-lives of some possible proton radioactivity candidates in NUBASE2020 that are energetically allowed or have been observed but not yet quantified. This work improves the accuracy of proton radioactivity studies and provides a robust theoretical framework for future nuclear structure research.
Comments:
22 pages, 5 figures, version accepted for publication in Eur. Phys. J. Plus
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.07960 [pdf]
Eur.Phys.J.Plus(2026)·0 citations
13
[Submitted on 9 Mar 2026]
Bayesian neural network with autoencoder for model-based description of $α$ -particle preformation factor
Xiao-Yan Zhu · Heng-Jian Si-Tu · Hao Zhang · Wei Gao · Wen-Bin Lin · Xiao-Hua Li
$α$ decay is an important probe for studying the structure of heavy and superheavy nuclei, in which the $α$ -particle preformation ( $P_{α}$ ) is a key physical quantity for describing decay half-lives. This work develops a hybrid framework that integrates Bayesian neural networks with autoencoder (BNN-Auto), combined with the cosh potential (CPT), to systematically optimize the constraint and prediction of $P_{α}$ . The model employs variational inference for probabilistic modeling of network weights, naturally providing robust uncertainty quantification for predictions, and utilizes an autoencoder to enhance the robustness of feature representation. Based on experimental data from 535 nuclei, the BNN-Auto method achieves relative improvements in the root mean square deviation ( $σ_{RMS}$ ) of $P_{α}$ prediction by $61.14%$ on the training set and $54.49%$ on the validation set. Further analysis reveals that the $P_{α}$ and half-life extracted by the model exhibit pronounced odd-even staggering and shell effects in isotopic chains with $Z = 86 - 90$ and isotones with $N = 124 - 128$ and $N = 150 - 154$ . Moreover, we successfully predict the $α$ decay half-lives of nuclei with $Z = 120$ and observe a significant increase in the half-life near $N = 184$ , which verifies the shell effect of the predicted 'stable island'. This study not only provides a high-precision theoretical description for $α$ decay, but also offers a new machine learning perspective for exploring the structure of superheavy nuclei.
Comments:
22 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.07976 [pdf]
0 citations
14
[Submitted on 9 Mar 2026]
Correlation between nuclear isospin asymmetry and $α$ -particle preformation probability for superheavy nuclei from a Bayesian inference
Xiao-Yan Zhu · Hao Zhang · Wei Gao · Wen-Jing Xing · Wen-Bin Lin · Xiao-Hua Li
In the study of $α$ decay within the superheavy nuclear region ( $Z \geq 90$ and $N \geq 140$ ), the $α$ -particle preformation probability $P_{α}$ serves as a crucial physical quantity linking nuclear structure to decay observables. We introduce a phenomenological model incorporating the decay energy $Q_{α}$ , mass number $A$ , orbital angular momentum $l$ , isospin asymmetry $I$ , and unpaired nucleon effect. For the first time, a Bayesian inference method combined with Markov Chain Monte Carlo (MCMC) sampling has been employed to impose global constraints on the model parameters, enabling the systematic and high-precision calculation of $P_{α}$ . The results reveal a significant suppressing effect of isospin asymmetry on $P_{α}$ , a finding independently corroborated by random forest-based feature importance analysis, which identified $I$ as a dominant factor. Furthermore, calculations using the maximum a posteriori (MAP) parameters not only reproduce the shell effect at $N = 152$ but also yield $α$ decay half-life predictions in excellent agreement with experimental ones, thereby validating this model universality. This work provides the first global analysis tool for probing the $α$ preformation mechanism in superheavy nuclei, underscores the potential of the Bayesian framework for inverting complex nuclear physics problems, and establishes a reliable theoretical benchmark for guiding future experimental exploration of superheavy nuclei.
Comments:
17 pages, 6 figures, version accepted for publication in Nucl. Sci. Tech
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.07983 [pdf]
0 citations
15
[Submitted on 9 Mar 2026]
The Birman-Schwinger operator for the Cornell Hamiltonian
O Civitarese🇦🇷 · S. Fassari🇮🇹 · M. Gadella🇪🇸 · F. Rinaldi🇮🇹
Quantum Chromodynamics is the theory of strong interactions. It has been shown during the last decades that it describes correctly most of the properties of hadrons at high energy. The most distinctive feature of the theory is the realisation that the elementary particles which composed the known forms of matter, that is to say quarks and gluons, cannot be observed at low energy. In this work we are addressing this specific feature, known as confinement, by performing a rigorous mathematical treatment of the Cornell potential
Comments:
17 pages, 25 references
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.08004 [pdf]
Eur.Phys.J.Plus(2025)·0 citations
16
[Submitted on 9 Mar 2026]
E0 transition strengths as a tool to constraint model parameters. Application to even-even Xe isotopes
P. Martin-Higueras · J.E. Garcia-Ramos
Background: In any nuclear structure model, the accurate description of E0 transition rates constitutes a significant challenge; at the same time, these observables provide a stringent constraint on the admissible parameter space of the model. Purpose: This work pretend to study the value of certain $ρ^{2} (E 0)$ values or ratios over the whole parameter space of the interacting boson model. As an application, the case of the even-even Xe isotopes will be explored. Method: The interacting boson model will be considered for the calculation of $ρ^{2} (E 0)$ values for some key transitions and to explore how these observables change over the parameter space of the model. Results: Several key $ρ^{2} (E 0)$ values or ratios are considered and contour plots in the parameter space of the interacting boson model (Casten triangle) are computed. The results for even-even Xe isotopes are superimposed on the contour plots. Conclusions: The presented analysis confirms that $ρ^{2} (E 0)$ values and, in particular, certain ratios allow to constraint the parameter space of the interacting boson model. There are certain regions where the $ρ^{2} (E 0)$ values cannot be altered by the fine tuning of the Hamiltonian parameters.
Comments:
19 pages, 9 captioned figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.08197 [pdf]
0 citations
17
[Submitted on 9 Mar 2026]
Microscopic quasifission dynamics of the $^{54} Cr +^{243} Am$ reaction
Liang Li · Lu Guo
Synthesizing superheavy elements (SHEs) like $Z = 119$ is severely hindered by the dominant quasifission (QF) channel, which prevents compound nucleus formation. Understanding QF dynamics is thus essential for future experiments. We investigate the QF mechanisms in the $^{54} Cr +^{243} Am$ reaction, a key candidate system for SHE 119, emphasizing the roles of projectile orientation and incident energy. Calculations are performed using the fully microscopic time-dependent Hartree-Fock theory based on the Skyrme energy density functional. We conduct systematic simulations covering a broad set of initial orientations of the deformed $^{54} Cr$ and $^{243} Am$ nuclei, alongside a finely spaced range of incident energies extending from below to well above the Coulomb barrier. Our fixed-energy results show that projectile side collisions are governed by shell effects driving heavy and light fragments toward spherical $Z = 82$ and deformed $N = 52 - 56$ closures, respectively, whereas tip collisions exhibit weaker shell influence. These shell-dominated reactions are characterized by shorter interaction times, attributed to the enhanced rigidity of shell-stabilized fragments accelerating neck rupture. The energy dependence reveals a complex evolution where the system transitions from an octupole-stabilized regime ( $Z \approx 88$ ) to a spherical shell-driven regime, with specific energy windows exhibiting suppressed shell influence. Our study demonstrates that the manifestation of shell effects in QF is a dynamical outcome sensitively dependent on both collision geometry and incident energy. Systematically probing this energy sensitivity is crucial for identifying optimal incident energies where the QF process exhibits suppressed shell influence, thereby potentially enhancing the fusion probability and improving the prospects for synthesizing new SHEs.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.08479 [pdf]
PRC(2026)·1 citation
18
[Submitted on 6 Mar 2026] (cross-list from astro-ph.HE)
Thermalization of Neutrinos in a Neutron Star Merger Simulation
Mark G. Alford🇺🇸 · Liam Brodie🇺🇸 · Francois Foucart🇺🇸 · Alexander Haber🇺🇸
We study the neutrino distributions that arise in a simulation of a neutron star merger that uses a Monte Carlo (MC) neutrino transport scheme. In a snapshot taken 1 ms after merger, we calculate relevant observables to test when neutrinos behave like a thermalized gas, and when a free-streaming picture is more appropriate. We find that in hot, dense regions where neutrino-matter interactions are frequent, MC neutrino and antineutrino distributions are consistent with thermalized neutrinos. In moderately warm regions, where neither approximation is expected to hold, we find significant departures from the predictions of the thermalized-neutrino approximation, particularly for the (anti)neutrino average opacity and net rate of absorption per baryon, even when average energies appear approximately thermal. At lower temperatures, MC results approach the free-streaming limit. Our results demonstrate that energy-averaged agreement with thermalized-neutrino assumptions does not guarantee accurate weak interaction rates. Non-equilibrium aspects of the neutrino distribution are therefore crucial for neutrino-mediated microphysics such as composition evolution in the early post-merger phase.
Comments:
v1: 14 pages and 8 figures. Code to generate and plot data: https://gitlab.com/liambrodie/neutrino-thermalization
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2603.06788 [pdf]
PRD(2026)·4 citations
19
[Submitted on 6 Mar 2026] (cross-list from astro-ph.HE)
Enhanced Neutrino Cooling from Parity-Doubled Nucleons in Neutron Star Cooling Simulations
Rodrigo Negreiros🇺🇸 · Liam Brodie🇺🇸 · Jan Steinheimer🇩🇪 · Veronica Dexheimer🇺🇸 · Robert D. Pisarski🇺🇸
Although restoration of chiral symmetry is predicted by quantum chromodynamics to take place at high baryon density, most modeling of neutron star interiors disregards a chiral phase transition. We model neutron star cores with a parity doublet model, which allows for dynamical chiral symmetry restoration and predicts the appearance of the parity partners of nucleons and hyperons at large densities, as well as deconfined quark matter. We study the thermal evolution of neutron stars, focusing for the first time on the impact of Urca processes involving the parity partners in neutron star cooling simulations. We find that Urca processes for the parity partners of the nucleons significantly affect the thermal evolution of massive stars and allow for improved agreement with observed surface temperature and ages.
Comments:
v1: 12 pages and 5 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2603.06789 [pdf]
5 citations
20
[Submitted on 8 Mar 2026] (cross-list from hep-ph)
Schwinger effect in QCD and nuclear physics
Hidetoshi Taya🇯🇵
We provide a pedagogical review of the Schwinger effect, i.e., the non-perturbative production of particle and anti-particle pairs from the vacuum by strong fields, as well as related strong-field phenomena. Beginning with an overview of the Schwinger effect in quantum electrodynamics, we discuss its extensions to quantum chromodynamics and its applications in nuclear physics, including high- $Z$ nuclei, string breaking, relativistic heavy-ion collisions, and the chiral anomaly.
Comments:
26 pages, 3 figures; a contribution to the Encyclopedia of Nuclear Physics
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th); Plasma Physics (physics.plasm-ph)
arXiv:
2603.07847 [pdf]
1 citation
21
[Submitted on 9 Mar 2026] (cross-list from hep-ph)
Physics-Informed Global Extraction of the Universal Small- $x$ Dipole Amplitude
Si-Wei Dai🇨🇳 · Fu-Peng Li🇨🇳 · Long-Gang Pang🇨🇳 · Guang-You Qin🇨🇳 · Shu-Yi Wei🇨🇳 · Han-Zhong Zhang🇨🇳 · Wenbin Zhao🇨🇳
We extract the universal small- $x$ dipole scattering amplitude $N (r, x_{B})$ from a global analysis based on a physics-informed neural network (PINN), without imposing a priori MV-type parametrization of the initial condition. The network provides a smooth and differentiable surrogate for $N (r, x_{B})$ , whose rapidity dependence is constrained by the collinearly improved Balitsky--Kovchegov evolution equation, while its functional form is simultaneously constrained by Deep Inelastic Scattering (DIS) data for the reduced total and charm cross sections, exclusive $J / ψ$ photoproduction measurements, and a positivity requirement for the momentum-space dipole amplitude. The resulting single universal amplitude consistently describes all fitted observables within a unified framework, alleviating the long-standing tension between total and charm channels encountered in conventional small- $x$ fits based on rigid parametric ansätze. Within the fitted kinematic domain, the best extracted PINN solution yields a smooth, non-negative momentum-space dipole over the full transverse-momentum range examined. Our results provide a robust and well-behaved input for Color Glass Condensate phenomenology across a broad class of high-energy processes.
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2603.08008 [pdf]
7 citations
22
[Submitted on 9 Mar 2026] (cross-list from hep-ph)
Heavy mesons with dynamical gluon on the light front
Jiatong Wu🇨🇳 · Hengfei Zhao🇨🇳 · Kaiyu Fu🇨🇳 · Zhi Hu🇨🇳 · Xingbo Zhao · James P. Vary🇨🇳
We investigate the structure of charmonium, bottomonium, and $B_{c}$ meson systems within the Basis Light-Front Quantization (BLFQ) approach, including both the quark-antiquark ( $∣ q q ˉ ⟩$ ) and quark-antiquark-gluon ( $∣ q q ˉ g ⟩$ ) Fock sectors. Our input light-front Hamiltonian incorporates a confining potential inspired by light-front holography, as well as the quark-gluon interaction from Quantum Chromodynamics. By adjusting model parameters to reproduce the mass spectra for low-lying states, we obtain the light-front wave functions for the heavy meson states. Based on these wave functions, we calculate electromagnetic form factors, decay constants, parton distribution amplitudes (PDAs), and parton distribution functions (PDFs) of the quarks and gluons in the heavy mesons. Our results for the charge radii and decay constants reasonably agree with experimental data and other theoretical approaches. The PDAs are consistent with the predictions from the earlier BLFQ calculations with an effective one-gluon exchange interaction. Furthermore, we present the first predictions within the BLFQ framework for the gluon PDFs in heavy mesons based on the light-front wave function in the $∣ q q ˉ g ⟩$ sector.
Comments:
20 pages, 70 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2603.08114 [pdf]
2 citations
23
[Submitted on 9 Mar 2026] (cross-list from astro-ph.SR)
s-process nucleosynthesis in low-mass AGB stars by the $^{13}$ C( $α$ ,n) $^{16}$ O neutron source
Inma Domínguez · Carlos Abia · Maurizio Busso · Oscar Straniero · Sara Palmerini
In this review we outline our knowledge on slow neutron captures, concentrating on its main part occurring during the final stages of stellar evolution for low or intermediate-mass stars when they evolve during the Asymptotic Giant Branch, or AGB, stars. We focus our attention on how, in this field, studies passed from a first era of inquiries based on nuclear systematics, to numerical nucleosynthesis computations performed in stellar codes. We then discuss how these last were forced, by observational constraints, to almost abandon, for the synthesis of nuclei between Sr and Pb, the rather naturally activated Ne22 neutron source (operating efficiently at T > 30 keV, and producing a neutron density N_n > 5 10^8 cm^-3). This implied considering the alternative reaction 13C(alpha,n)16O, that can be activated locally after each of the TDU. The mentioned crucial reaction occurs at T< 8 keV, in the time intervals separating two subsequent thermal pulses (TP). The layers where 13C(alpha,n)16O operates are characterized by a radiative equilibrium and their low temperature also yields low values for the neutron density (N_n < 10^7 cm^-3).
Comments:
19 pages, 8 figures, accepted for publication in EJP
Subjects:
Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2603.08140 [pdf]
EPJA(2026)·1 citation
24
[Submitted on 9 Mar 2026] (cross-list from hep-ph)
Connecting baryon light-front wave functions to quasi-transverse-momentum-dependent correlators in lattice QCD
S. Rodini🇮🇹 · A. Schiavi🇮🇹 · B. Pasquini🇮🇹
Within light-front quantization, hadrons can be represented on a Fock-space basis of configurations of elementary partons. The coefficients of the expansion are called light-front wave functions (LFWFs), and encode all the dynamical degrees of freedom. We show how to extract the LFWFs of baryons, such as the proton, from equal-time correlators suitable for Lattice QCD simulations. Using an operator product expansion, we prove the factorization of the relevant correlator in the three-quark color-singlet LFWF, a residual lattice factor, and a soft factor that systematically subtracts the additional divergences arising from the factorization. We verify up to next-to-leading order the independent renormalizability of the LFWF, and we derive the evolution equations that govern its scale dependence.
Comments:
17 pages, 9 figures, consistent with published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2603.08405 [pdf]
PRD(2026)·0 citations
25
[Submitted on 9 Mar 2026] (cross-list from hep-ph)
Radiative corrections to the nucleon isovector $g_{V}$ and $g_{A}$
Oleksandr Tomalak🇨🇳 · Yi-Bo Yang🇨🇳
Electroweak, QCD, and QED radiative corrections to the nucleon low-energy coupling constants $g_{V}$ and $g_{A}$ are enhanced by large perturbative logarithms between the electroweak and hadronic scale, as well as between the hadronic scale and the low-energy MeV scale. Additionally, higher-order pion-mass splitting corrections to the nucleon axial-vector charge might be large. By consistently incorporating these effects, we provide an updated relation between the lattice-QCD and physical $g_{A}$ , finding a total radiative correction of $3.5 (2.1) %$ ( $5.6 (0.7) %$ ). This leads to an expected lattice-QCD result of $g_{A}^{QCD} = 1.265 (26)$ ( $g_{A}^{QCD} = 1.240 (9)$ ) when based on a combination of lattice-QCD and data-driven (or only data-driven) inputs, respectively. Future phenomenological, chiral perturbation theory, and lattice-QCD studies can improve both the central value and the uncertainty of this estimate.
Comments:
11 pages, 2 figures, version published in Universe, footnote 1 added, new sentence in footnote 3, corrected last equation in footnote 5, minor text changes
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2603.08596 [pdf]
Universe(2026)·10 citations

Affiliations

first authorsco-authorsvia INSPIRE