PaperPanorama

Nuclear Theory·nucl-th

Wednesday·June 11, 2025

12 papers5 primary·7 cross-listed

  1. 01

    Estimation of Electron Screening Potential in the 6Li(d,{\alpha})4He Reaction Using Multi-Layer Perceptron Neural Network

    D. Chattopadhyay

    Reactions between light charged nuclei at sub-Coulomb energies are crucial in astrophysical environments, but accurate cross-section measurements are hindered by electron screening. Traditional methods, including polynomial extrapolation and the Trojan Horse Method, often yield screening potentials exceeding adiabatic predictions. Building on the success of an MLP-based Artificial Neural Network (ANN) for the 6Li(p, {\alpha})3He reaction [1], this work applies the same approach to the 6Li(d, {\alpha})4He reaction. Experimental astrophysical S-factor data from literature are reanalyzed using the ANN to model the energy-dependent S-factor. The bare S-factor is extracted from data above 70 keV, where screening effects are minimal, and the screening potential is obtained by comparing with the low-energy region. The resulting screening potential is 147.95 eV, demonstrating the robustness of ANN-based methods for evaluating electron screening in low-energy nuclear reactions involving light nuclei.

    nucl-thRadiat.Phys.Chem.(2026)·0 citations
  2. 02

    Bulk Viscosity of Two-Flavor Color Superconducting Quark Matter in Neutron Star Mergers

    Mark Alford🇺🇸 · Arus Harutyunyan🇦🇲 · Armen Sedrakian🇵🇱 · Stefanos Tsiopelas🇵🇱

    This work investigates the bulk viscosity of warm, dense, neutrino-transparent, color-superconducting quark matter, where damping of density oscillations in the kHz frequency range arises from weak-interaction-driven direct Urca processes involving quarks. We study the two-flavor red-green paired color-superconducting (2SC) phase, while allowing for the presence of unpaired strange quarks and blue color light quarks of all flavors. Our calculations are based on the SU(3) Nambu-Jona-Lasinio (NJL) model, extended to include both vector interactions and the `t Hooft determinant term. The primary focus is on how variations in the NJL Lagrangian parameters -- specifically, the diquark and vector coupling strengths -- affect both the static properties of quark matter, such as its equation of state and composition, and its dynamical behavior, including bulk viscosity and associated damping timescales. We find that the bulk viscosity and corresponding damping timescale can change by more than an order of magnitude upon varying the vector coupling by a factor of two at high densities and by a lesser degree at lower densities. This sensitivity primarily arises from the susceptibility of 2SC matter, with a smaller contribution from modifications to the weak interaction rates. In comparison, changes in the diquark coupling have a more limited impact. The damping of density oscillations in 2SC matter is similar quantitatively to nucleonic matter and can be a leading mechanism of dissipation in merging hybrid stars containing color superconducting cores. -

    nucl-thastro-ph.HEFront.Astron.Space Sci.(2025)·10 citations
  3. 03

    Microscopic analysis of the giant monopole resonance excitation energy

    M.K. Gaidarov🇧🇬 · M.V. Ivanov🇧🇬 · Y.I. Katsarov🇧🇬 · A.N. Antonov🇧🇬 · I.C. Danchev🇮🇳

    A systematic study of the isoscalar giant monopole resonance (ISGMR) in a wide range of nuclei from various isotopic chains is performed within the microscopic self-consistent Skyrme HF+BCS method and coherent density fluctuation model (CDFM). The calculations for the nuclear incompressibility are based on the Brueckner and Barcelona-Catania-Paris-Madrid (BCPM) energy density functionals for nuclear matter using the capability of the CDFM to make a transition to the corresponding incompressibility in finite nuclei. The results obtained by applying of different definitions of the ISGMR energy, as well as the two energy-density functionals, are analyzed and compared with the available experimental data. The consideration includes the peculiarities of the proton and neutron density distributions and their corresponding linear size characteristics. In general, a connection with the measured neutron skin thicknesses is proposed as a possible way for realistic estimations of the energy of ISGMR.

    nucl-thPRC(2025)·1 citation
  4. 04

    Symmetry energy and neutron matter equation of state at from the electric dipole polarizability in Ca, Ni and Pb

    Mengying Qiu🇨🇳 · Lie-Wen Chen🇨🇳 · Zheng Zheng Li🇨🇳 · Yi Fei Niu🇨🇳 · Zhen Zhang🇨🇳

    Based on the quasiparticle random phase approximation implemented via the finite amplitude method, we employ a set of representative relativistic mean-field models to investigate the sensitivity of the inverse electric dipole polarizability in , , and to the symmetry energy and the neutron matter equation of state at a subsaturation density of . Combined with predictions from nonrelativistic Skyrme energy density functionals (EDFs), our results reveal strong linear correlations between and both and . In particular, the -- correlation for is found to be nearly model-independent. A Bayesian analysis of the measured values of in , , and yields quantitative constraints of and at the 68\% (90\%) confidence level, respectively. The extracted value of exceeds most predictions from microscopic many-body theories, suggesting a mild tension between nuclear EDF-based constraints derived from data and results from \textit{ab initio} calculations.

    nucl-thPRC(2025)·2 citations
  5. 05

    Heavy-heavy and heavy-light mesons in cold nuclear matter

    J. J. Cobos-Martínez🇲🇽 · Guilherme N. Zeminiani🇧🇷 · Kazuo Tsushima🇧🇷

    We review the in-medium modifications of effective masses (Lorentz scalar potentials or phenomenon of mass shift) of heavy-heavy and heavy-light mesons in symmetric nuclear matter and their nuclear bound states. We use a combined approach with the quark-meson coupling (QMC) model and an effective Lagrangian. As demonstrated by the cases of pionic and kaonic atoms, studies of meson-nucleus bound state can provide us with important information on chiral symmetry in dense nuclear medium. In this review, we treat the mesons, , and , where our emphasys is on the heavy mesons. In addition, we also present some new results for the -nucleus bound states.

    nucl-thhep-exhep-phnucl-exSymmetry(2025)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE