Nuclear Theory·nucl-th

Thursday·July 24, 2025

14 papers—6 primary·8 cross-listed

01
Angular correlations in neutron-gamma reactions
Vladimir Gudkov · Hirohiko M. Shimizu
Angular correlations for low-energy neutron induced $γ$ reactions are calculated using nuclear reaction formalism for multi level neutron capture with arbitrary multiplicities of $γ$ transitions. We confirm previous calculations [V. V. Flambaum and O. P. Sushkov, Nucl. Phys.A 435 , 352 (1985)] for dipole transitions obtained with different formalism. The possible applications of n- $γ$ correlations for studies of symmetry violations and electromagnetic transitions are discussed.
nucl-thhep-phPRC(2025)·0 citations
02
Hypernuclei with Neural Network Quantum States
Andrea Di Donna🇮🇹 · Lorenzo Contessi🇫🇷 · Alessandro Lovato🇮🇹 · Francesco Pederiva🇮🇹
Leveraging complementary machine-learning-based approaches, we compute properties of $s$ - and $p$ -shell $Λ$ hypernuclei - including binding energies, single-particle densities, and radii - starting from the individual interactions among their constituents. These interactions are modeled using an improved leading-order pionless effective field theory expansion, with coefficients determined via a Gaussian Process framework anchored on virtually exact few-body techniques. We solve the many-body Schrödinger equation using a variational Monte Carlo method based on neural network quantum states, extending it for the first time to include $Λ$ particles alongside protons and neutrons. The predicted binding energies show remarkably good agreement with experimental results, given the simplicity of the input Hamiltonian. We also confirm the experimentally observed shrinkage of the proton radius in $_{Λ}^{7}$ Li compared to its parent nucleus, $^{6}$ Li. This work paves the way for an ab initio description of medium-mass and heavy hypernuclei, as well as for understanding the onset of strange degrees of freedom in the core of neutron stars.
nucl-thPRResearch(2026)·11 citations
03
Probing $ϕ$ N interaction through bound states of $ϕ N- α$ system
Faisal Etminan🇮🇷
The possible bound state of the $ϕN α$ system is explored within the framework of the three-body cluster model. The calculations are done by employing the state-of-the-art $ϕ$ N interactions obtained from the analysis of the pure elastic scattering and the coupled-channel in the $ϕp$ correlation functions. The $ϕ α$ potentials are constructed by two methods: the single-folding potential (SFP) method for the given spin-averaged $ϕ$ N potentials in coordinate space, and the optical model potential (OMP) approximation within the multiple-scattering framework for the given scattering length of the $ϕ$ N interaction. It is found that, when only the single-channel $ϕN$ interactions are employed, the $ϕN α$ system could be bound with a binding energy in the interval [3-26] MeV. However, the coupled-channel $ϕp$ interaction, which is most consistent with experimental measurements, does not yield any bound state, even when the spin-averaged $ϕN$ potential is employed, and this potential is found to be more attractive than the corresponding coupled-channel counterpart. It is essential to consider the contributions from the dynamics of the vector-baryon coupled channels $ϕp$ interaction. This effect is capable of playing a decisive role in the existence of mesic nuclei.
nucl-thhep-latPRC(2025)·4 citations
04
Further steps towards next generation of covariant energy density functionals
B. Osei · A. V. Afanasjev · A. Taninah · A. Dalbah · U. C. Perera · V. A. Dzuba · V. V. Flambaum
The present study aims at further development of covariant energy density functionals (CEDFs) towards more accurate description of binding energies across the nuclear chart. For the first time, infinite basis corrections to binding energies in the fermionic and bosonic sectors of the covariant density functional theory have been taken into account in the fitting protocol within the covariant density functional theory. In addition, total electron binding energies have been used in the conversion of atomic binding energies into nuclear ones. Their dependence on neutron excess has been investigated for the first time across the nuclear chart within atomic approach. These factors have been disregarded in previous generation of covariant energy density functionals but their neglect leads to substantial global calculation errors for physical quantities of interest. For example, these errors for binding energies are of the order of 0.8 MeV or higher for the three major classes of covariant energy density functionals.
nucl-thPRC(2025)·6 citations
05
Implications of the recent neutron decay measurements on the properties of compact objects -- a dark star with nucleonic shell ?
M.Veselský🇨🇿 · V. Petousis🇨🇿 · Ch.C. Moustakidis🇬🇷 · M. Vikiaris🇬🇷
Recent experimental observation suggests that neutron decay is always accompanied by emission of electron while in 1% of cases proton is not emitted. We develop a scenario kinematically compatible with experimental observation, where neutron decay results in production of two dark matter particles of about half the mass of neutron and test properties of neutron stars with admixture of such particles. Constraints on mass and coupling to vector dark boson are obtained. The structure of the compact object is modified to a dark star with a shell of nucleonic matter around the nuclear saturation density.
nucl-thastro-ph.HEhep-ph2 citations
06
Simultaneous improvements of nuclear mass and charge radius predictions using multi-task Gaussian process approaches
Weihu Ye · Niu Wan
A multi-task Gaussian process (GP) machine learning model is introduced to simultaneously predict two important nuclear observables across the nuclear chart, namely nuclear masses and charge radii. Utilizing 12 physical input features, our multi-task GP consistently outperforms single-task learning, achieving overall root-mean-square deviations of 0.136 MeV for masses and 0.007 fm for charge radii. The good performance of the present model is confirmed by three complementary validations, namely various fractions for training and testing data, further extrapolations for newly reported nuclei far from stability, and popular Garvey-Kelson mass relations. The correlations between the two observables are explicitly analyzed within the multi-task learning framework. Furthermore, by employing the SHapley Additive exPlanations (SHAP) method, we interpret the importance of different features for mass and radius predictions across distinct nuclear regions. These results demonstrate the effectiveness of the multi-task GP approach for high-accuracy nuclear property predictions.
nucl-thPRC(2026)·3 citations
07
Impact of 3D macro physics and nuclear physics on the p nuclei in O-C shell mergers
Joshua Issa · Falk Herwig · Pavel Denissenkov · Marco Pignatari
O-C shell mergers in massive stars are a site for producing the p nuclei by the $γ$ process, but 1D stellar models rely on mixing length theory, which does not match the radial velocity profiles of 3D hydrodynamic simulations. We investigate how 3D macro physics informed mixing impacts the nucleosynthesis of p nuclei. We post-process the O-shell of the $M_{ZAMS} = 15 M_{⊙}$ , $Z = 0.02$ model from the NuGrid stellar data set. Applying a downturn to velocities at the boundary and increasing velocities across the shell as obtained in previous results, we find non-linear, non-monotonic increase in p-nuclei production with a spread of 0.96 dex, and find that isotopic ratios can change. Reducing C-shell ingestion rates as found in 3D simulations suppresses production, with spreads of 1.22-1.84 dex across MLT and downturn scenarios. Applying dips to the diffusion profile to mimic quenching events also suppresses production, with a 0.51 dex spread. We analyze the impact of varying all photo-disintegration rates of unstable n-deficient isotopes from Se-Po by a factor of 10 up and down. The nuclear physics variations for the MLT and downturn cases have a spread of 0.56-0.78 dex. We also provide which reaction rates are correlated with the p nuclei, and find few correlations shared between mixing scenarios. Our results demonstrate that uncertainties in mixing arising from uncertain 3D macro physics are as significant as nuclear physics and are crucial for understanding p-nuclei production during O-C shell mergers quantitatively.
↳ astro-ph.SRnucl-thApJ(2026)·5 citations
08
Quantifying alpha clustering in the ground states of 16-O and 20-Ne
E. Harris · M. Barbui · J. Bishop · G. Chubarian · Sebastian Konig · E. Koshchiy · K.D. Launey · Dean Lee · Zifeng Luo · Yuan-Zhuo Ma · Ulf-G. Meissner · C.E. Parker and 9 other authors
Understanding the role of multi-nucleon correlations in the structure of light nuclei is at the forefront of modern nuclear science. In this letter, we present a quantitative benchmark study of alpha-cluster correlations in the ground states of 16-O and 20-Ne. Experimental data provide direct evidence that the wave functions of the ground states of 16-O and 20-Ne are dominated by alpha-cluster correlations, in agreement with the predictions of sophisticated nuclear structure models. We also provide a new model-independent constraint for the alpha asymptotic normalization coefficient of the 16-O ground state and discuss the implications of these findings on the 12-C(alpha,gamma)16-O reaction, which is of critical importance for nuclear astrophysics.
↳ nucl-exastro-ph.SRnucl-th4 citations
09
Novel insight into centre-vortex geometry in four dimensions
Jackson A. Mickley🇦🇺 · Chris Allton🇬🇧 · Ryan Bignell🇮🇪 · Derek B. Leinweber🇦🇺
Centre-vortex surfaces are mapped out in four dimensions within the framework of SU(3) lattice gauge theory to understand the role of secondary loops that develop in three-dimensional visualisations of centre-vortex structure, appearing separate from the percolating cluster. Loops that initially appear disconnected in three-dimensional slices can originate from the same connected surface in four dimensions depending on the surface's curvature. For the first time, these secondary loops are identified as "connected" or "disconnected" with respect to the vortex sheet, allowing new insight into the evolution of centre-vortex geometry through the finite-temperature phase transition. At low temperatures, we find that secondary loops of any length primarily lie in the same sheet percolating the four-dimensional volume. Only a handful of small secondary sheets disconnected from the percolating sheet are identified. Above the phase transition, the vortex structure is still found to be dominated by a single large sheet but one that has aligned with the temporal dimension. With the near absence of any curvature orthogonal to the temporal dimension, connected secondary loops become vanishingly rare. Other novel quantities, such as the four-dimensional density of secondary sheets and the sheet sizes themselves, are analysed to build a complete picture of centre-vortex geometry in four dimensions.
↳ hep-lathep-phnucl-thPRD(2025)·3 citations
10
Threshold cusp structures in multi-channel scattering
Katsuyoshi Sone · Tetsuo Hyodo
We study the behavior of the cusp structures focusing on the isospin symmetry breaking effects. The properties of the exotic hadrons are reflected in the shape of the cusp structures. In realistic hadron scatterings, the threshold energies of the isospin partners appear within a small energy region. For a detailed analysis of such systems, it is essential to study the behavior of the cusp structures arising at two closely spaced thresholds. In this work, we introduce a convenient formulation of the scattering amplitude and demonstrate that the cusp structures at two nearby thresholds are related through the isospin symmetry.
↳ hep-phnucl-thPoS(2026)·3 citations
11
Convergence in charmonium structure: light-front wave functions from basis light-front quantization and Dyson-Schwinger equations
Xianghui Cao🇨🇳 · Yang Li🇨🇳 · Chao Shi🇨🇳 · James P. Vary🇺🇸 · Qun Wang🇨🇳
We present a systematic comparison of charmonium light-front wave functions obtained through two complementary non-perturbative approaches: Basis Light-Front Quantization (BLFQ) and Dyson-Schwinger equations (DSE). Key observables include the charge form factor, gravitational form factors, light-cone distribution amplitudes, decay constants, and two-photon transition form factors. Despite their distinct theoretical foundations and model parameters, the predictions from BLFQ and DSE exhibit remarkable agreement across all observables. This convergence validates both frameworks for studying charmonium structure and highlights the complementary strengths of Hamiltonian-based (BLFQ) and Lagrangian-based (DSE) methods in addressing non-perturbative QCD.
↳ hep-phhep-thnucl-thPRD(2026)·1 citation
12
Dihadron fragmentation framework for near-side energy-energy correlators
Zhong-Bo Kang🇺🇸 · Andreas Metz🇺🇸 · Daniel Pitonyak🇺🇸 · Congyue Zhang🇺🇸
We establish an approach to analyze the free hadron and transition (nonperturbative) regions of near-side energy-energy correlators (EECs) based on dihadron fragmentation functions (DiFFs). We introduce a (nonperturbative) function we call the "EEC-DiFF" and explicitly show that expanding it for large relative transverse momentum between the two hadrons gives the $O (α_{s})$ expression for the "EEC jet" function used in the quark/gluon (perturbative) region. This connection indicates that a formal theoretical matching will be able to bridge the free hadron, transition, and quark/gluon regions and allow all of them to be analyzed simultaneously. We further derive a result valid for near-side EECs in the free hadron and transition regions of $e^{+} e^{-}$ annihilation in terms of the EEC-DiFF. Using a simple model for the function, we perform the first fit within the dihadron framework to experimental data in this regime. We find reasonable agreement with the measurements and reproduce the salient features of near-side EECs in the free hadron and transition regions.
↳ hep-phhep-exnucl-exnucl-thPRL(2026)·27 citations
13
Solving two and three-body systems with deep neural networks
Ruitian Li🇨🇳 · Xuan Luo🇨🇳 · Hao Sun🇨🇳 · Pablo G. Ortega🇪🇸
We develop a new method for solving two- and three-body bound state problems using unsupervised machine learning techniques. We use a deep neural network to calculate both simple and realistic potentials, obtaining the properties of the deuteron and triton bound states for the chiral effective field theory NN potential. Our results provide significant accuracy with no prior assumptions about the behaviour of the wave function. This neural network technique, which extends from two-body to three-body, may provide insight into potential solutions to the nuclear and hadronic many-body problems.
↳ hep-phnucl-thEPJC(2026)·3 citations
14
Collinear limit of the energy-energy correlator in $e^{+} e^{-}$ collisions: transition from perturbative to non-perturbative regimes
Enrico Herrmann🇺🇸 · Zhong-Bo Kang🇺🇸 · Jani Penttala🇺🇸 · Congyue Zhang🇺🇸
We study the collinear limit of the energy-energy correlator (EEC) in $e^{+} e^{-}$ collisions, focusing on the transition from the perturbative QCD regime at relatively large angles to the non-perturbative region at small angles. To describe this transition, we introduce a non-perturbative jet function and perform a global analysis at NNLO+NNLL accuracy using experimental data spanning center-of-mass energies from $Q = 29.0$ to $91.2$ GeV. This marks the first accurate description of the EEC across the entire near-side region ( $0^{\circ} < χ < 9 0^{\circ}$ ) within a unified theoretical framework. Our analysis also provides, for the first time, a quantitative extraction of the non-perturbative contribution to the EEC quark jet function, identifying a characteristic transition scale around $2.3$ GeV - distinct from the scale observed in EEC-in-jet measurements in $pp$ collisions at the LHC, which are dominated by gluon jets. These results offer the first evidence for flavor dependence (quark vs. gluon) in the EEC and provide new insights into the interplay between perturbative and non-perturbative QCD dynamics.
↳ hep-phhep-exhep-thnucl-ex+121 citations

Affiliations

first authorsco-authorsvia INSPIRE