Nuclear Theory·nucl-th

Friday·January 3, 2025

23 papers—11 primary·12 cross-listed

01
Erratum: Exact solutions to the fermion propagator Schwinger-Dyson equation in Minkowski space with on-shell renormalization for quenched QED \newline [Phys. Rev. D 96, 036021 (2017)]
Shaoyang Jia · Michael R. Pennington
With the introduction of a spectral representation, the Schwinger--Dyson equation (SDE) for the fermion propagator is formulated in Minkowski space in QED. After imposing the on-shell renormalization conditions, numeric solutions for the fermion propagator spectral functions are obtained in four dimensions with a renormalizable version of the Gauge Technique Ansatz for the fermion-photon vertex in the quenched approximation in the Yennie gauge. Despite the limitations of this model, having an explicit solution provides a guiding example of the fermion propagator with the correct analytic structure.
nucl-thhep-ph0 citations
02
Bayesian analysis of hybrid neutron star EOS constraints within an instantaneous nonlocal chiral quark matter model
Alexander Ayriyan🇵🇱 · David Blaschke🇵🇱 · Juan Pablo Carlomagno🇦🇷 · Gustavo A. Contrera🇦🇷 · Ana Gabriela Grunfeld🇦🇷
We present a physics-informed Bayesian analysis of equation of state constraints using observational data for masses, radii and tidal deformability of pulsars and a generic class of hybrid neutron star equation of state with color superconducting quark matter on the basis of a recently developed nonlocal chiral quark model. The nuclear matter phase is described within a relativistic density functional model of the DD2 class and the phase transition is obtained by a Maxwell construction. We find the region in the two-dimensional parameter space spanned by the vector meson coupling and the scalar diquark coupling, where three conditions are fulfilled: (1) the Maxwell construction can be performed, \mbox{(2) the maximum} mass of the hybrid neutron star is not smaller than \mbox{2.0 M $_{⊙}$ } and (3) the onset density of the phase transition is not below the nuclear saturation density $n_{0} = 0.15$ fm $^{- 3}$ . The result of this study shows that the favorable neutron star equation of state has low onset masses for the occurrence of a color superconducting quark matter core between 0.5-0.7 $M_{⊙}$ and maximum masses in the range 2.15-2.22 $M_{⊙}$ . In the typical mass range of 1.2-2.0 $M_{⊙}$ , the radii of these stars are between 11.9 and 12.4 km, almost independent of the mass. In principle, hybrid stars would allow for larger maximum masses than provided by the hadronic reference equation of state.
nucl-thastro-ph.HEhep-phUniverse(2025)·20 citations
03
Systematic study of large-momentum distribution in nuclei with the operator product expansion
Jiexin Yu🇨🇳 · Bingwei Long🇨🇳
The operator product expansion (OPE) is applied in conjunction with Pionless effective field theory to study the short-rang structure of nuclei. By matching the OPE with the selected nuclear potentials for nucleon-nucleon scattering states, we obtain the Wilson coefficients. The nucleon momentum distribution in the deuteron is then used to test the OPE against the predictions of these nuclear potentials. In order to achieve a systematic separation of short-range and long-range interactions, we discuss how the OPE approximation can be improved by including higher-order EFT potentials and higher-dimension local operators.
nucl-thPRC(2025)·1 citation
04
Deep learning for exploring hadron-hadron interactions
Lingxiao Wang🇯🇵
In this proceeding, we introduce deep learning technologies for studying hadron-hadron interactions. To extract parameterized hadron interaction potentials from collision experiments, we employ a supervised learning approach using Femtoscopy data. The deep neural networks (DNNs) are trained to learn the inverse mapping from observations to potentials. To link between experiments and first-principles simulations, we further investigate hadronic interactions in Lattice QCD simulations from the HAL QCD method perspective. Using an unsupervised learning approach, we construct a model-free potential function with symmetric DNNs, aiming to learn hadron interactions directly from simulated correlation functions (equal-time Nambu-Bethe-Salpeter amplitudes). On both fronts, deep learning methods show great promise in advancing our understanding of hadron interactions.
nucl-thhep-latJ.Subatomic Part.Cosmol.(2025)·5 citations
05
Closed-form formulas in number-conserved pairing theory
G. J. Fu
In this work, I present closed-form formulas for the norm and many-body density matrices between general wave functions with exact particle numbers in pairing theory, using properties of the generalized Kronecker delta. These formulas, expressed as sums of minors and Pfaffians, apply to both even and odd particle-number systems and accommodate pair condensate as well as broken-pair configurations. This formalism directly facilitates applications in the generator coordinate method and symmetry restoration techniques, including angular momentum projection.
nucl-th1 citation
06
Reexamination of nuclear structure properties and shape coexistence of nuclei around A70
Jameel-Un Nabi · Tuncay Bayram · Mahmut Boyukata · Asim Ullah · Anes Hayder · Syeda Zainab Naqvi
We reexamine the nuclear structure properties of waiting point nuclei around A70 using the interacting boson model 1 (IBM 1) and the relativistic mean field (RMF) model. Effective density dependent meson exchange functional (DD ME2) and density dependent point coupling functional (DD PC1) were used for the RMF calculations. We calculated the energy levels, the geometric shapes, binding and separation energies of nucleons and quadrupole deformation parameters (\b{eta}2). The shape coexistence phenomena in A 70 nuclei (68Se, 70Se, 70Br, 70Kr, 72Kr, 74Kr, 74Rb, and 74Sr) was later investigated. Spherical and deformed shapes of the selected waiting point nuclei were computed using the IBM 1 and RMF models, respectively. The proton neutron quasiparticle random phase approximation (pn QRPA) model was used to calculate \b{eta} decay properties (Gamow Teller strength distributions, \b{eta} decay half lives, and branching ratios) of selected nuclei as a function of \b{eta}2. The results revealed a significant variation in calculated half lives and Gamow Teller strength distributions as the shape parameter was changed. The \b{eta}2 computed via DD ME2 functional resulted in half lives in best agreement with the measured data.
nucl-thastro-ph.SRNPA(2024)·0 citations
07
General features of the stellar matter equation of state from microscopic theory, new maximum-mass constraints, and causality
Francesca Sammarruca🇺🇸 · Tomiwa Ajagbonna🇺🇸
The profile of a neutron star probes a very large range of densities, from the density of iron up to several times the density of saturated nuclear matter, and thus no theory of hadrons can be considered reliable if extended to those regions. We emphasize the importance of taking contemporary ab initio theories of nuclear and neutron matter as the baseline for any extension method, which will unavoidably involve some degree of phenomenology. We discuss how microscopic theory, on the one end, with causality and maximum-mass constraints, on the other, set strong boundaries to the high-density equation of state. We present our latest neutron star predictions where we combine polytropic extensions and parametrizations guided by speed of sound considerations. The predictions we show include our baseline neutron star cooling curves.
nucl-thFront.Astron.Space Sci.(2025)·2 citations
08
Unexpected Rise in Nuclear Collectivity from Short-Range Physics
Kevin S. Becker · Kristina D. Launey · Andreas Ekström · Tomáš Dytrych · Daniel Langr · Grigor H. Sargsyan · Jerry P. Draayer
We discover a surprising relation between the collective motion of nucleons within atomic nuclei, traditionally understood to be driven by long-range correlations, and short-range nucleon-nucleon interactions. Specifically, we find that quadrupole collectivity in low-lying states of $^{6}$ Li and $^{12}$ C, calculated with state-of-the-art ab initio techniques, is significantly influenced by two opposing $S$ -wave contact couplings that subtly alter the surface oscillations of one largely deformed nuclear shape, without changing that shape's overall contribution within the nucleus. The results offer new insights into the nature of emergent nuclear collectivity and its link to the underlying nucleon-nucleon interaction at short distances.
nucl-thPRL(2026)·8 citations
09
Isospin effect on the liquid-gas phase transition for finite nuclei
S. Mallik
The phenomenon of nuclear liquid-gas phase transition is a topic of contemporary interest. In heavy-ion collisions, there is no direct way of accessing the thermodynamic variables like pressure, density, free energy, entropy etc., and unambiguous detection of phase transition becomes difficult. A peak in the first order derivative of total multiplicity with respect to temperature (commonly abbreviated as the multiplicity derivative) has been established as a new experimentally accessible signature of the nuclear liquid-gas phase transition. In this work, the effect of isospin asymmetry in the fragmenting system, as well as the nuclear equation of state, on the multiplicity derivative and specific heat at constant volume is investigated within the framework of the Canonical Thermodynamical Model (CTM) with a semi-microscopic cluster functional.
nucl-thhep-phnucl-exNPA(2025)·3 citations
10
White Paper on Software Infrastructure for Advanced Nuclear Physics Computing
P. M. Jacobs🇺🇸 · A. Boehnlein🇺🇸 · B. Sawatzky🇺🇸 · J. Carlson🇺🇸 · I. Cloet🇺🇸 · M. Diefenthaler🇺🇸 · R. G. Edwards🇺🇸 · K. Godbey🇺🇸 · W. R. Hix🇺🇸 · K. Orginos🇺🇸 · T. Papenbrock🇺🇸 · M. Ploskon🇺🇸 and 40 other authors
This White Paper documents the discussion and consensus conclusions of the workshop "Software Infrastructure for Advanced Nuclear Physics Computing" (SANPC 24), which was held at Jefferson Lab on June 20-22, 2024. The workshop brought together members of the US Nuclear Physics community with data scientists and funding agency representatives, to discuss the challenges and opportunities in advanced computing for Nuclear Physics in the coming decade. Opportunities for sustainable support and growth are identified, within the context of existing and currently planned DOE and NSF programs.
nucl-thhep-phnucl-ex3 citations
11
Validation and extrapolation of atomic mass with physics-informed fully connected neural network
Yiming Huang · Jinhui Chen · Jiangyong Jia · Lu-Meng Liu · Yu-Gang Ma · Chunjian Zhang
Machine learning offers a powerful framework for validating and predicting atomic mass. We compare three improved neural network methods for representation and extrapolation for atomic mass prediction. The powerful method, adopting a macroscopic-microscopic approach and treating complex nuclear effects as output labels, achieves superior accuracy in AME2020, yielding a much lower root-mean-square deviation of 0.122 MeV in the test set, significantly lower than alternative methods. It also exhibits a better extrapolation performance when predicting AME2020 from AME2016, with a root-mean-square deviation of 0.191 MeV. We further conduct sensitivity analyses against the model inputs to verify interpretable alignment beyond statistical metrics. Incorporating theoretical predictions of magic numbers and masses, our fully connected neural networks reproduce key nuclear phenomena including nucleon pairing correlation and magic number effects. The extrapolation capability of the framework is discussed and the accuracy of predicting new mass measurements for isotope chains has also been tested.
nucl-thnucl-exPRC(2025)·14 citations

Affiliations

first authorsco-authorsvia INSPIRE