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Nuclear Theory·nucl-th

Tuesday·August 11, 2026

12 papers—7 primary·5 cross-listed

All12Primary7Cross-lists5
  1. 01

    [Submitted on 8 Aug 2026]

    On three-cluster resonance structure of hypernuclei He, Li and Be

    N. K. Kalzhigitov · S. Amangeldinova · V. O. Kurmangaliyeva · V. S. Vasilevsky

    The bound and resonance states of hypernuclei He, Li and Be are studied within a three-cluster model. Within this model, hypernuclei He, Li and Be are considered as three-cluster systems He++, He++, He++, respectively. Special attention is paid to determining resonance states in the three-cluster continuum of these hypernuclei and to study their nature. One semi-realistic nucleon-nucleon potential is employed to determine the internal structure of the clusters He, , and , and their interaction. Three versions of the nucleon-hyperon potential, known as the YNG potential, are employed to determine the interaction of the listed clusters with the lambda hyperon. A set of very narrow and fairly wide resonance states is found in the three-cluster continuum of He, Li and Be. The narrowest resonance states were detected in He and Li and their total width does not exceed 10 keV. The dominant decay channels of these resonance states are revealed.

    Comments:
    53 pages, 21 figures, 16 tables, typos corrected
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2608.07930 [pdf]
    0 citations
  2. 02

    [Submitted on 9 Aug 2026]

    White dwarf-neutron star matter transition and the effect of light elements

    Yao Ma · Yong-Liang Ma · Ruo-Xi Wu · Yue-Liang Wu

    White dwarfs and neutron stars are unique laboratories for dense nuclear matter physics. We develop a single relativistic mean-field framework that treats both classes of compact star, and the transition between them, on the same footing: the nuclei of white-dwarf matter are solved self-consistently as Wigner-Seitz cells with the full electromagnetic interaction, while the same Lagrangian yields the uniform nuclear matter of the neutron-star interior. Within this unified description we compute light-element white dwarfs seeded by He, C, and O, following each fixed- sequence along its neutronization path and connecting it to the neutron-star branch through exact Maxwell junctions, from which the corresponding mass-radius relations are derived. The helium- and carbon-seeded white-dwarf sequences attain maximum masses of and , respectively. On the neutron-star branch, the retained light-element envelope changes the predicted radii only at the percent level---by approximately km at , within current observational uncertainties. Providing a consistent zero-temperature equation of state from white-dwarf to neutron-star densities, this unified framework offers a natural starting point for studies of white-dwarf--neutron-star binary mergers, progenitor-star evolution, decihertz gravitational-wave sources, and related multimessenger phenomena.

    Comments:
    13 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2608.08824 [pdf]
    0 citations
  3. 03

    [Submitted on 9 Aug 2026]

    Large Amplitude Collective Motion and Dissipation in the Ground State and the First Isomeric Wells in the Neutron-Induced Fission of U

    Ibrahim Abdurrahman · Matthew Kafker · Aurel Bulgac · Ionel Stetcu

    In fission induced by low energy neutrons, the mother nucleus spends a significant fraction of the time in the ground state and isomer wells, eventually passing beyond the outer barrier, where the primary fission fragments properties are defined. Despite this, the dynamics of these two early stages have not been investigated using microscopic models. This study examines the evolution of the mother nucleus in both wells separately, using time-dependent density functional theory, which has been previously used to treat the saddle-to-scission stage of fission for U(n,f) reactions. These two early stages of fission are essential blocks in the final theory of the formation and evolution of a compound nucleus. The present study shows that the dynamics in both wells is strongly dissipative, similar to the dynamics from saddle to scission. It also reveals that while the initial mass asymmetry of the system quickly settles to very small fluctuations in the ground state well, in the isomeric well, the mass asymmetry oscillates with a rather large amplitude, in almost harmonic motion. Furthermore, with low probability, neutrons are emitted in both wells.

    Comments:
    5 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2608.08875 [pdf]
    1 citation
  4. 04

    [Submitted on 10 Aug 2026]

    Hadron-quark phase transitions along proto-neutron-star evolution

    P. Laskos-Patkos🇬🇷 · P.S. Koliogiannis🇭🇷 · Ch.C. Moustakidis🇬🇷

    The new era of multi-messenger astronomy requires the accurate and self-consistent derivation of the nuclear equation of state at high temperature. In the present work, we focused on the calculation of hot hybrid equations of state, studying the different evolution stages of a proto-neutron star with a quark matter core (proto-hybrid star). For the hadronic matter we used two distinct Skyrme effective interactions, while for quark matter the well-known vector MIT bag model was employed. To model the era of trapped neutrinos in the system we considered the global conservation of lepton fraction which resulted in an equation of state with an extended mixed phase. For periods following the neutrino diffusion phase of a proto-neutron star, the equations of state were modelled using both the Maxwell and the Gibbs construction depending on the assumption for either local or global electric-charge conservation. With the use of the derived hybrid models, we solved the Tolman-Oppenheimer-Volkov equations to describe the corresponding hybrid star configurations. Finally, we investigated how the structure of proto-hybrid stars evolves, using constant rest mass sequences. We found that regardless of whether electric-charge is globally or locally conserved, the earlier stages of a hybrid star's life may play a crucial role on the determination of its maximum possible gravitational mass in later stages.

    Comments:
    v1: 17 pages, 6 figures, 1 table
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
    arXiv:
    2608.09195 [pdf]
    0 citations
  5. 05

    [Submitted on 10 Aug 2026]

    Long-lived opposite-parity states and the onset of octupole collectivity in atomic nuclei

    Bui Minh Loc · Hoang Thai An · Nguyen Le Anh · Panagiota Papakonstantinou · Naftali Auerbach

    Octupole deformation in atomic nuclei is of interest for both nuclear structure and precision tests of fundamental symmetries, but identifying regions of octupole collectivity remains challenging. We analyze low-energy spectra of odd-mass nuclei and uncover a previously unrecognized empirical regularity that serves as a signature of octupole collectivity in neighboring even-even systems. The observed patterns, which can be understood within a core-coupling picture, are consistent with previous theoretical studies and lead to predictions for neutron-rich and proton-deficient nuclei. These findings provide a simple empirical guide for identifying promising candidates for future experiments and microscopic calculations.

    Comments:
    6 pages, 1 figure
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2608.09386 [pdf]
    0 citations
  6. 06

    [Submitted on 10 Aug 2026]

    Neutron radii and semi-phenomenological treatment of neutron distributions for Mg isotopes

    Govind Kumar · M. Imran · Z. Hasan · Z. A. Khan

    Involving the charge radii of \rm Mg isotopes, as calculated using the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc), we have extracted the neutron radii of \rm Mg isotopes by studying their reaction cross sections () from \rm C at 240 MeV/nucleon within the framework of Glauber model. The calculations use (i) descriptions of nuclei in terms of the Slater determinant involving harmonic oscillator single-particle wave functions (SDHO), and (ii) two-parameter Fermi (2pF) shape of density distribution, with the aim to assess the density dependence of neutron skin in \rm Mg isotopes. To understand the asymptotic behavior (spread) of neutron distribution, we propose to introduce the use of core+n () or core+2n () description for stable as well as unstable isotopes; () is the one-neutron (two-neutron) separation energy of the considered isotope. The core+n (core+2n) is treated semi-phenomenologically. In this work, the core+n is employed for \rm Mg isotopes, and is subjected to reproduce the same neutron radius of the given isotope, as we obtained from calculations. To validate the core+n description, we have revisited the reaction cross sections of \rm Mg isotopes. The results are found to agree well with the experimental values. Moreover, the core+n neutron distributions clearly demonstrate the one-neutron halo structure of \rm Mg. These findings motivated us to use the core+2n description for the neutron distribution of \rm Mg in predicting its neutron radius, and from \rm C at 240 and 1000 MeV/nucleon. The trend of the neutron radius and suggests that \rm Mg exhibits two-neutron halo like structure.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2608.09429 [pdf]
    0 citations
  7. 07

    [Submitted on 10 Aug 2026]

    A Gaussian Process framework for constraining the nuclear equation of state from microscopic calculations with correlated uncertainties

    Y. G. Lee · J. Kim · T. Zhao · C. Drischler

    We present constraints on the nuclear equation of state (EOS) from microscopic asymmetric matter calculations at zero temperature based on chiral nucleon-nucleon and three-nucleon interactions. The constraints include the saturation point, the isospin dependence of the incompressibility, and the symmetry energy, as well as the crust-core transition density of neutron-star matter. To quantify and propagate correlated uncertainties from noisy many-body calculations to derived observables, we introduce GPDiff, an efficient JAX-based Python package for multivariate Gaussian process (GP) regression with automatic differentiation. After training, GPDiff enables joint predictions of the EOS and derivatives of arbitrary order with respect to the input variables, including mixed partial derivatives. In this initial application, we analyze recent high-order many-body perturbation theory calculations of asymmetric matter up to about twice saturation density and explore nonstationary change-surface kernels, a class of input-dependent kernels, for modeling the EOS. GPDiff is broadly applicable to microscopic nuclear EOS calculations at zero and finite temperature and provides a versatile package for GP-based uncertainty quantification and inference of the nuclear EOS.

    Comments:
    30 pages, 13 figures, 2 tables
    Subjects:
    Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex)
    arXiv:
    2608.09678 [pdf]
    0 citations

Affiliations

first authorsco-authorsvia INSPIRE