Nuclear Theory·nucl-th

Friday·June 7, 2024

7 papers—4 primary·3 cross-listed

01
Impact of correlations on nuclear binding energies
Alberto Scalesi🇫🇷 · Thomas Duguet🇫🇷 · Pepijn Demol🇧🇪 · Mikael Frosini🇫🇷 · Vittorio Somà🇫🇷 · Alexander Tichai🇩🇪
A strong effort will be dedicated in the coming years to extend the reach of ab initio nuclear-structure calculations to heavy doubly open-shell nuclei. In order to do so, the most efficient strategies to incorporate dominant many-body correlations at play in such nuclei must be identified. With this motivation in mind, the present work pedagogically analyses the inclusion of many-body correlations and their impact on binding energies of Calcium and Chromium isotopes. Employing an empirically-optimal Hamiltonian built from chiral effective field theory, binding energies along both isotopic chains are studied via a hierarchy of approximations based on polynomially-scaling expansion many-body methods. The corresponding results are compared to experimental data and to those obtained via valence-space in-medium similarity renormalization group calculations at the normal-ordered two-body level that act as a reference in the present study. The spherical mean-field approximation is shown to display specific shortcomings in Ca isotopes that can be understood analytically and that are efficiently corrected via the consistent addition of low-order dynamical correlations on top of it. While the same setting cannot appropriately reproduce binding energies in doubly open-shell Cr isotopes, allowing the unperturbed mean-field state to break rotational symmetry permits to efficiently capture the static correlations responsible for the phenomenological differences observed between the two isotopic chains. Eventually, the present work demonstrates in a pedagogical way that polynomially-scaling expansion methods based on unperturbed states that possibly break (and restore) symmetries constitute an optimal route to extend ab initio calculations to heavy closed- and open-shell nuclei.
nucl-thEPJA(2024)·14 citations
02
$_{Ξ}^{5} H$ hypernuclei by folding the state-of-the-art $Ξ N$ interactions
Faisal Etminan🇮🇷
I examined a phenomenological Nijmegen and a first principles HAL QCD $Ξ N$ potentials to study $α Ξ$ ineractions. A Woods-Saxon type form for $α Ξ$ potential in the single-folding potential approach is derived by using the spin- and isospin averaged $Ξ N$ interactions. The possibility of resonance or bound state is searched and accordingly, the low energy scattering phase shift parameters of $α Ξ$ are calculated. The numerical results show that even though two $Ξ N$ potentials have significantly dissimilar isospin (I) and spin (S) components, $_{Ξ}^{5} H$ could be only a Coulomb-assisted resonance state that appears about $0.5$ MeV below the threshold of $α + Ξ^{-}$ for both model of potentials.
nucl-thhep-ph0 citations
03
Evidence for strong isovector nuclear spin-orbit interaction
Tong-Gang Yue🇨🇳 · Zhen Zhang🇨🇳 · Lie-Wen Chen🇨🇳
The nucleon spin-orbit interaction is a cornerstone of nuclear structure theory, yet its isospin dependence remains elusive owing to the lack of clean experimental probes. Here we show that the charge-weak form factor difference in $^{48}$ Ca, recently extracted in a model-independent manner by the CREX experiment, exhibits strong sensitivity to the isovector spin-orbit interaction. Using Skyrme-like energy density functionals, we demonstrate that a significantly enhanced isovector spin-orbit interaction, about four times stronger than conventional parametrizations, can resolve the PREX-CREX puzzle, which has challenged modern nuclear theories and our understanding of nuclear symmetry energy, while maintaining a good description of nuclear bulk properties and well-established shell structure of finite nuclei. This enhanced isovector spin-orbit interaction also provides a novel mechanism for the emergence of the $N = 14$ , $16$ , $32$ and $34$ magic numbers in neutron-rich nuclei on the mean-field level. These findings point to a strong isospin dependence of the nucleon spin-orbit interaction, which is expected to have important implications for nuclear structures, electroweak nuclear processes, and related problems in nuclear astrophysics.
nucl-thastro-ph.HEhep-phnucl-exSci.Bull.(2026)·23 citations
04
Genetic Programming for the Nuclear Many-Body Problem: a Guide
Illya Bakurov · Pablo Giuliani · Kyle Godbey · Nathaniel Haut · Wolfgang Banzhaf · Witold Nazarewicz
Genetic Programming is an evolutionary algorithm that generates computer programs, or mathematical expressions, to solve complex problems. In this Guide, we demonstrate how to use Genetic Programming to develop surrogate models to mitigate the computational costs of modeling atomic nuclei with ever increasing complexity. The computational burden escalates when uncertainty quantification is pursued, or when observables must be globally computed for thousands of nuclei. By studying three models in which the mean field depends on the total particle density self-consistently, we show that by constructing reduced order models supported by Genetic Programming one can speed up many-body computations by several orders of magnitude with a negligible loss in accuracy
nucl-thJ.Phys.G(2025)·5 citations
05
Does the Sun have a Dark Disk?
Gustavo F. S. Alves🇺🇸 · Susan Gardner🇺🇸 · Pedro Machado🇺🇸 · Mohammadreza Zakeri🇺🇸
The Sun is not quite a perfect sphere, and its oblateness, thought to be induced through its rotation, has been measured using optical observations of its radius. Its gravitational quadrupole moment can then be deduced using solar models, or through helioseismology, and it can also be determined from measurements of its gravitational effects on Mercury's orbit. The various assessments do not appear to agree, with the most complete and precise orbital assessments being in slight excess of other determinations. This may speak to the existence of a non-luminous disk or ring, where we also note evidence for a circumsolar dust ring within Mercury's orbit from the Solar TErrestrial RElations Observatory (STEREO) mission. Historically, too, a protoplanetary disk may have been key to reconciling the Sun's metallicity with its neutrino yield. The distribution of the non-luminous mass within Mercury's orbit can modify the relative size of the optical and orbital quadrupole moments in different ways. We develop how we can use these findings to limit the mass of a dark disk, ring, or halo in the immediate vicinity of the Sun, and we note how future observational studies of the inner solar system can not only refine these constraints but also help to identify and to assess the mass of its dark-matter component.
↳ hep-phastro-ph.EPastro-ph.HEnucl-thPRD(2025)·1 citation
06
Light quark mass dependence of nucleon mass to two-loop order
Long-Bin Chen🇨🇳 · Siwei Hu🇨🇳 · Yu Jia🇨🇳 · Zhewen Mo🇨🇳
We investigate the nucleon self energy through the sixth chiral order in the covariant $S U (2)$ chiral perturbation theory ( $χ$ PT) in the single baryon sector. The validity of the extended on-mass-shell (EOMS) renormalization scheme is explicitly verified to two-loop order, manifested by the miraculous cancellation of all nonlocal divergences and power-counting-breaking (PCB) terms that are nonanalytic in pion mass. Using the $σ_{π N}$ term determined from the latest lattice simulation to constrain some unknown higher-order low energy constants (LECs), we predict the nucleon mass in the chiral limit to be $856.6 \pm 1.7$ MeV. It is found that the EOMS scheme exhibits quite satisfactory convergence behavior through $O (q^{6})$ around physical point. We also predict the pion mass dependence of the nucleon mass to the accuracy of $O (q^{6})$ , which is in satisfactory agreement with the recent lattice results over a wide range of pion mass.
↳ hep-phhep-latnucl-th10 citations
07
Evolution of the transverse-momentum dependent gluon distribution at small $x$
Paul Caucal🇫🇷 · Edmond Iancu🇫🇷
Using the colour dipole picture for photon-nucleus interactions at small $x$ together with the Color Glass Condensate (CGC) effective theory, we demonstrate that the next-to-leading (NLO) order corrections to the cross-section for the inclusive production of a pair of hard jets encode not only the JIMWLK evolution with decreasing $x$ , but also the DGLAP evolution of the gluon distribution function and the CSS evolution of the gluon transverse momentum dependent (TMD) distribution. The emergent CSS equation takes the form of a rate equation describing the evolution of the dijet distribution in the transverse momentum imbalance $K_{⊥}$ when increasing the dijet relative momentum $P_{⊥}$ . All three types of evolution become important when both $P_{⊥}$ and $K_{⊥}$ are much larger than the nuclear saturation momentum $Q_{s} (x)$ and we propose a framework which encompasses all of them. The solution to the JIMWLK equation provides the source term for the DGLAP evolution with increasing $K_{⊥}$ , which in turn generates the initial condition for the CSS evolution with increasing $P_{⊥}$ .
↳ hep-phnucl-thPRD(2025)·27 citations

Affiliations

first authorsco-authorsvia INSPIRE

Impact of correlations on nuclear binding energies

Ξ5​H hypernuclei by folding the state-of-the-art ΞN interactions

Evidence for strong isovector nuclear spin-orbit interaction

Genetic Programming for the Nuclear Many-Body Problem: a Guide

Does the Sun have a Dark Disk?

Light quark mass dependence of nucleon mass to two-loop order

Evolution of the transverse-momentum dependent gluon distribution at small x

Affiliations

$_{Ξ}^{5} H$ hypernuclei by folding the state-of-the-art $Ξ N$ interactions

Evolution of the transverse-momentum dependent gluon distribution at small $x$