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Nuclear Theory·nucl-th

Monday·February 24, 2025

7 papers—4 primary·3 cross-listed

All7Primary4Cross-lists3
  1. 01

    Hypernuclear cluster states of Unveiled through Neural Network-Driven Microscopic Calculation

    Jiaqi Tian · Mengjiao Lyu · Zheng Cheng · Masahiro Isaka · Akinobu Dote · Takayuki Myo · Hisashi Horiuchi · Hiroki Takemoto · Niu Wan · Qing Zhao

    We investigate the hypernuclear cluster states of using a neural-network-driven microscopic model. We extend the Control Neural Networks (Ctrl.NN) method and systematically calculate the positive-parity spectrum of . By incorporating -shell excitations and parity-coupling effects into the hypernuclear system, we reveal structural changes, including clustering effects and new configurations such as isosceles-triangle and -- linear-chain structures. Furthermore, by comparing with experimental data, we identify that many peaks (6 and 8) can be interpreted as dominant states, which is consistent with shell-model predictions. Notably, based on our analysis of the excited states of , we propose possible candidates for previously unexplained or controversial experimental peaks.

    nucl-thPLB(2025)·7 citations
  2. 02

    Kubo formulas for spin polarization in dissipative relativistic spin hydrodynamics: a first-order gradient expansion approach

    Matteo Buzzegoli (West University of Timisoara)🇷🇴

    We use linear response theory to derive both the non-dissipative and dissipative effects of spin polarization for massive and massless interacting spin 1/2 particles in a relativistic fluid. We list and classify all the possible contributions up to first order in gradients of hydrodynamic fields including the axial chemical potential and the spin potential, and we obtain the corresponding Kubo formulas. We find that all the possible dissipative contributions, except those coming from the gradients of spin potential, require a chiral imbalance or parity violating interactions. In a fluid with chiral imbalance we find a chiral version of the spin Hall effect, i.e. a spin polarization is induced by the gradients of temperature and of axial chemical potential in the direction orthogonal to the momentum of the particle and to the gradients. Moreover, we identify several other new non-dissipative contributions that are not present for free fields.

    nucl-thJHEP(2025)·8 citations
  3. 03

    Examination of the multiple-scattering expansion in the four-nucleon system

    A. Deltuva

    The elastic neutron- scattering at intermediate energies is studied using rigorous integral equations solved in the momentum-space partial-wave basis. The four-particle transition operators are expanded into multiple-scattering series in terms of subsystem transition operators. Various approximations resulting from truncation of the series in different ways are evaluated and their validity is investigated. They fail at lower energies but at higher energies provide a rough reproduction of exact results at small scattering angles. In the large-angle region all approximations fail heavily, indicating that the scattering amplitude results from a delicate interplay of many multiple-scattering terms. The partial-wave analysis reveals that the developed approximations are reliable in higher partial waves, and for practical calculations an efficient ``hybrid'' approach is proposed, combining exact amplitudes in lower partial waves with approximations in higher partial waves. The implications for often used approximation of the first order in two-body transition matrix and development of microscopic optical potentials are discussed.

    nucl-thnucl-exPRC(2025)·0 citations
  4. 04

    Projective Imaging of High-Energy Nuclei via Coherent Exclusive Vector Meson Production in Electron-Nucleus Collisions

    Maci Kesler🇺🇸 · Ashik Ikbal Sheikh🇺🇸 · Rongrong Ma🇺🇸 · Zhoudunming Tu🇺🇸 · Thomas Ullrich🇺🇸 · Zhangbu Xu🇺🇸

    One of the major goals of modern nuclear experiments is to study the distributions of gluons inside nuclei at high energy. A key measurement is the coherent exclusive vector meson (VM) production in diffractive electron-nucleus collisions, where the gluon spatial distribution inside the nucleus can be obtained through a Fourier transform of the squared nuclear momentum transfer () distribution. This research aims to overcome the two main obstacles of the measurement: limited precision in measuring arising from the momentum resolution of the outgoing electron and the overwhelming incoherent background. We demonstrate that by measuring the projected distribution along the direction perpendicular to the electron scattering plane, the effect of the outgoing electron's momentum resolution can be effectively mitigated, and the diffractive pattern is largely restored. Furthermore, we propose to measure the angular distribution of the VM's decay daughters to statistically remove the incoherent background.

    nucl-thhep-phnucl-exPLB(2026)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE