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Nuclear Theory·nucl-th

Wednesday·October 1, 2025

13 papers—6 primary·7 cross-listed

All13Primary6Cross-lists7
  1. 01

    Shape polarization and coexistence of high- three-quasiparticle states in odd-mass isotones

    Runyan Dong · Changfeng Jiao

    Three-quasiparticle -isomeric states in odd-mass isotones within the mass region are systematically investigated using configuration-constrained potential energy surface calculations. The calculations successfully reproduce the excitation energies and deformations of known high- isomers in the nuclei from Tm to Re. For the nuclei closer to the shell closure (Ir, Au, and Tl), predictions for the configurations of observed and yet-to-be-observed isomers are provided. The results reveal strong shape polarization, where the three-quasiparticle states are driven to larger deformations compared to the often shape-soft or spherical ground states. A particularly rich spectrum of shape coexistence is predicted in Tl, where several high- three-quasiparticle configurations with distinct prolate, oblate, and triaxial shapes are found to coexist at similar excitation energies. Notably, the oblate-deformed configuration at keV is proposed to be responsible for a long-lived isomer. This study provides a comprehensive picture of shape evolution and coexistence in high- multi-quasiparticle states, offering valuable insights for future experimental research.

    nucl-thnucl-ex0 citations
  2. 02

    Pre-equilibrium charm quark dynamics and their impact on D-Meson observables

    Manu Kurian🇮🇳 · Mayank Singh🇺🇸 · Charles Gale🇨🇦 · Sangyong Jeon🇨🇦 · Björn Schenke🇺🇸

    We study the impact of pre-equilibrium evolution on the charm quark and in Pb+Pb collisions at = 5.02 TeV. We observe that there is significant diffusion in the pre-equilibrium evolution, but there is no measurable effect on the final state observables.

    nucl-thhep-phEPJ Web Conf.(2026)·0 citations
  3. 03

    Multi-strangeness matter from ab initio calculations

    Hui Tong🇩🇪 · Serdar Elhatisari🇸🇦 · Ulf-G. Meißner🇩🇪 · Zhengxue Ren🇨🇳

    Hypernuclei and hypernuclear matter connect nuclear structure in the strangeness sector with the astrophysics of neutron stars, where hyperons are expected to emerge at high densities and affect key astrophysical observables. We present the first {\em ab initio} calculations that simultaneously describe single- and double- hypernuclei from the light to medium-mass range, the equation of state for -stable hypernuclear matter, and neutron star properties. Despite the formidable complexity of quantum Monte Carlo~(QMC) simulations with multiple baryonic degrees of freedom, by combining nuclear lattice effective field theory with a newly developed auxiliary-field QMC algorithm we achieve the first sign-problem free {\em ab initio} QMC simulations of hypernuclear systems containing an arbitrary number of neutrons, protons, and hyperons, including all relevant two- and three-body interactions. This eliminates reliance on the symmetry-energy approximation, long used to interpolate between symmetric nuclear matter and pure neutron matter. Our unified calculations reproduce hyperon separation energies, yield a neutron star maximum mass consistent with observations, predict tidal deformabilities compatible with gravitational-wave measurements, and give a trace anomaly in line with Bayesian constraints. By bridging the physics of finite hypernuclei and infinite hypernuclear matter within a single {\em ab initio} framework, this work establishes a direct microscopic link between hypernuclear structure, dense matter composition, and the astrophysical properties of neutron stars.

    nucl-thastro-ph.HEastro-ph.SRhep-lat+19 citations
  4. 04

    Initial spin fluctuations in heavy-ion collisions and where to find them

    Giuliano Giacalone🇨🇭 · Enrico Speranza🇮🇹

    Collective spin phenomena in the final states of heavy-ion collisions are typically understood to originate from vorticity and shear in the quark-gluon plasma. Here, we ask whether spin could already be present in the initial condition of the collisions. In particular, we argue that if a spin density exists at the beginning of the QGP expansion, it should experience event-by-event fluctuations due to the finite number of participant nucleons. In this contribution, we propose a simple model of fluctuating spin initial conditions for event-by-event spin hydrodynamics based on the Glauber Monte Carlo paradigm. We postulate that, if the net spin of the events is conserved from the initial to the final state, then initial state fluctuations of spin should manifest in specific spin correlations of hyperons. Within our picture, we predict that this signal is much larger in central O+O collisions than in central Pb+Pb collisions.

    nucl-thhep-exhep-phnucl-exEPJ Web Conf.(2026)·0 citations
  5. 05

    Electromagnetic moments of ground and excited states calculated in heavy odd-N open-shell nuclei

    J. Dobaczewski · A. E. Stuchbery · G. Danneaux · A. Nagpal · P. L. Sassarini · H. Wibowo

    Within nuclear DFT, we calculated spectroscopic magnetic dipole and electric quadrupole moments for various quasiparticle configurations of odd-, even-, nuclei ranging from gadolinium to osmium. By tagging the blocked quasiparticles with single-particle states of the semi-magic dysprosium isotope, we efficiently computed 22 prolate and 22 oblate states for each of the 154 nuclei and tracked them across the entire major neutron shell. We compared this extensive set of theoretical results with experimental data for 82 states in the region. Breaking rotational, time-reversal, and signature symmetries, we aligned the intrinsic angular momenta along the axis of axial symmetry, thereby enabling full shape- and spin-self-consistent polarizations. The spectroscopic moments were then obtained by restoring rotational symmetry. We conducted a detailed analysis of the pattern of agreement and disagreement between theory and experiment in individual nuclei. For the magnetic dipole moments, agreement with the data varies and is characterized by an overall average and RMS deviation of 0.11 and 0.35 , respectively. For the electric quadrupole moments, a good corresponding agreement of 0.16 b and 0.29 b was observed.

    nucl-thPRC(2026)·4 citations
  6. 06

    Nuclear state and level densities of actinides with the shell-model Monte Carlo

    D. DeMartini🇺🇸 · Y. Alhassid🇺🇸

    Actinides are of great interest in astrophysics and technology applications since they can fission. However, the microscopic calculation of their statistical properties in the presence of correlations poses a major theoretical challenge. The configuration-interaction shell-model is a suitable framework to calculate these properties but the required large model spaces are beyond the reach of conventional diagonalization methods. The shell-model Monte Carlo (SMMC) method enables calculations in very large model spaces and was applied to nuclei as heavy as the lanthanides. Here, we extend the SMMC method to the actinides. Fifteen even-even and odd-mass actinides Th, U, Pu, Cm, and Cf are studied using a single-particle model space that is larger than one major shell each for protons and neutrons, with a total dimension of the many-particle space as large as . We calculate nuclear state densities of these actinides and find they are strongly enhanced in comparison with mean-field densities. We use spin projection methods to calculate nuclear level densities and average -wave neutron resonance spacings, both of which are found to be in good agreement with experiments.

    nucl-th0 citations

Affiliations

first authorsco-authorsvia INSPIRE