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Nuclear Theory·nucl-th

Monday·June 29, 2026

13 papers—6 primary·7 cross-listed

All13Primary6Cross-lists7
  1. 01

    Single- and Double- Hypernuclear Correlations Calibrate Interaction Energies

    Shi Yuan Ding · Bao Yuan Sun

    Double- hypernuclei are essential for probing the interaction in the double-strangeness sector, yet the scarcity of experimental data severely limits systematic predictions. We present an evaluation framework based on nuclear many-body theory that exploits the intrinsic structural similarity between single- and double- systems to transfer empirical constraints from the well-mapped sector to the sector. By analyzing theoretical deviations of binding energies in light single- and double- hypernuclei, we identify a robust linear correlation between two sectors. This correlation enables a statistical evaluation of double- separation energies () and interaction energies () for heavier double- hypernuclei, by drawing on a wealth of empirical data from the single- sector with quantified uncertainties. Our results show that evaluated values, while consistent with existing data, are systematically larger than direct relativistic density functional predictions constrained only by the NAGARA event. This discrepancy suggests that standard mean-field-based extrapolations may underestimate correlations and other many-body effects, motivating an evaluation-based correction that offers crucial benchmarks for future experiments at facilities such as HIAF and J-PARC.

    nucl-th0 citations
  2. 02

    Oblate-prolate shape mixing and E0 transition in 28Si

    Yasutaka Taniguchi · Masaaki Kimura

    Background: oblate-prolate shape coexistence in Si has been discussed for decades, but the degree of shape mixing between these configurations remains poorly constrained. Purpose: We constrain the oblate-prolate mixing amplitudes in Si using available experimental information and discuss the inter-band E0 transition strength. Methods: Oblate and prolate and configurations are obtained by antisymmetrized molecular dynamics combined with the generator coordinate method. Using these configurations as the basis states, we constrain the mixing amplitudes by simultaneously reproducing the measured charge radius, the quadrupole moment of the state, and the in-band and inter-band values. The strength of the density-dependent term in the Gogny interaction is also varied within a reasonable range. Results: In the ground state, the oblate component is dominant, and the prolate component in the ground state is limited to less than about . For the state, the allowed prolate component is smaller than that in the ground state. The present analysis does not tightly constrain the corresponding E0 transition strength, but an upper limit of is obtained. Conclusions: The low-lying states of Si may exhibit substantial oblate-prolate mixing. A measurement of the inter-band E0 transition strength would provide a quantitative determination of the mixing amplitude.

    nucl-thnucl-ex1 citation
  3. 03

    Universal EOS-Radius Inverse Mappings Govern Precision-Dependent Inference of the Neutron Star Equation of State

    Bao-An Li

    Bayesian inference of the neutron star (NS) equation of state (EOS) generally assumes that improved observations primarily reduce posterior uncertainties while leaving inferred EOS parameters unchanged. Using mock measurements of the radius of a canonical NS with identical central values but varying observational precisions, we show that the inferred posterior means of EOS parameters can shift systematically as the measurement uncertainty changes. We demonstrate that this behavior originates from previously unidentified nearly universal inverse mappings between the NS radius and empirical EOS parameters. Across a broad range of observational precisions, posterior samples collapse onto nearly unique functions. These mappings are largely independent of observational precision and define a low-dimensional EOS manifold underlying Bayesian inference. We show that the precision dependence of inferred EOS parameters arises from nonlinear filtering of the posterior radius distribution through these mappings. In the narrow-distribution limit this effect reduces to a Jensen-type correction proportional to the local curvature of the inverse mapping, while for presently realistic uncertainties the full nonlinear-filtering relation accurately reproduces the posterior means. Our results reveal a geometric origin of precision-dependent inference in NS EOS studies and provide a new framework for connecting astrophysical observations directly to microscopic nuclear many-body theories.

    nucl-thastro-ph.HEhep-phhep-th+12 citations
  4. 04

    Efficient calculation of two-neutrino double-beta-decay nuclear matrix elements

    Mihai Horoi🇺🇸

    Reliable nuclear matrix elements (NMEs) are essential for interpreting double-beta-decay experiments and for connecting measured or constrained half-lives to the underlying weak-interaction physics. The two-neutrino mode () is allowed by the Standard Model and has been observed in several nuclei, whereas the neutrinoless mode () remains the key experimental signature of lepton-number violation and Majorana neutrino masses. Recent statistical shell-model studies indicate a strong correlation between the and NMEs, making accurate and efficient calculations of the former especially useful for assessing the latter. Direct evaluations of NMEs usually require summing over many states in the intermediate odd-odd nucleus, a procedure that becomes expensive and may converge slowly in large model spaces. We present and test an improved strength-function method based on Lanczos iterations that avoids full diagonalization while preserving the accuracy of explicit summation where such benchmarks are possible. The method is applied to several experimentally important emitters and to different effective Hamiltonians. We also show that the same framework can be used for the higher-order NMEs entering Taylor-expanded phase-space treatments of and related decay modes.

    nucl-thhep-ph0 citations
  5. 05

    QCD critical surface from constant entropy contours

    Hitansh Shah🇺🇸 · Tristan Gyure🇺🇸 · Anabella Leon🇺🇸 · Francesco Di Clemente🇺🇸 · Mauricio Hippert🇧🇷 · Claudia Ratti🇺🇸 · Volodymyr Vovchenko🇺🇸

    We provide the first mapping of the critical surface in (2+1)-flavor QCD in the full space, anchored on lattice QCD results at vanishing chemical potentials and obtained within an expansion along contours of constant entropy density. In the pure direction, this framework yields a critical point at MeV. Here we extend the construction to arbitrary directions in the three-dimensional chemical-potential space, parametrized by spherical coordinates , with the radial expansion truncated at . The resulting two-dimensional surface carries a direction-dependent critical temperature and baryochemical potential , which quantify the shift of the critical point relative to the pure direction. We find that increases by 40-100 MeV along the approximately strangeness neutral direction [--, ] relevant for heavy-ion collisions, while the critical temperature stays essentially unchanged. In the charge-neutral, weak-equilibrium direction~[--, ] relevant for neutron star mergers, the critical point, and the associated first-order phase transition, remain present at essentially the same location in the plane. We find no evidence for a critical point at large isospin densities, , relevant for cosmic trajectories in the early Universe, nor along the pure electric-charge or strangeness directions, at least outside the regions where pion or kaon condensation may occur.

    nucl-thhep-ph0 citations
  6. 06

    Bridging Ab Initio Symmetries and Global Nuclear Masses with Interpretable Neural Networks

    Phong Dang · Evander Espinoza · Xiaoliang Wan · Michela Negro · Jerry P. Draayer · Feng Pan · Tomas Dytrych · Daniel Langr · David Kekejian

    Ab initio modeling has established Wigner's SU(4) and Elliott's SU(3) as dominant symmetries of the nuclear force in light and intermediate-mass nuclei. We ask whether they also govern nuclear binding across the entire chart. Our aim is not high-precision prediction but physical insight, through interpretable, symmetry-based models. From the SU(3) and SU(4) Casimir operators we construct three neural-network (NN) mass models: Feature-Informed NN (FINN) for point predictions, Gaussian-Informed NN (GINN) adding uncertainty quantification, and Wigner-Informed NN (WINN) -- a mass formula using the Casimirs as an operator basis. All are trained on AME2016 and validated on nuclei new to AME2020. The SU(4) operators alone cut the root-mean-square error (RMSE) by nearly half on train and test data, and by about a fifth on extrapolation, relative to the liquid-drop baseline -- showing that Wigner's symmetry carries predictive information beyond bulk properties. Despite its compact form, WINN reaches the lowest validation RMSE, 0.430 MeV -- competitive with state-of-the-art mass models -- which we read less as a benchmark than as evidence that its symmetry basis captures important physics. WINN further reveals i) an enhancement of the quadratic SU(4) Casimir near the neutron dripline, signaling restoration of Wigner's symmetry, and ii) an unexpected gain of the quartic operator in the superheavy region. We thereby elevate emergent symmetries from the hidden order within individual nuclei to a governing principle of the whole nuclear chart.

    nucl-thcs.LG0 citations

Affiliations

first authorsco-authorsvia INSPIRE