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Nuclear Theory·nucl-th

Monday·July 20, 2026

8 papers—4 primary·4 cross-listed

All8Primary4Cross-lists4
  1. 01

    [Submitted on 17 Jul 2026]

    Growth of quartet correlations in neutron-rich Tellurium isotopes within quartet Bardeen-Cooper-Schrieffer theory

    Yixin Guo · Hiroyuki Sagawa · Masaaki Kimura

    Quartet correlations in neutron-rich Te isotopes are investigated within the quartet Bardeen-Cooper-Schrieffer (BCS) framework. Taking Sn as an inert core, we consider two valence protons and valence neutrons occupying the model space, and solve the quartet BCS variational equations with a charge-independent isovector pairing interaction. The effective pairing strength is constrained from empirical neutron pairing gaps in the Te isotopic chain. We find that the valence quartet number increases as the valence neutron number is enlarged from to . The same increasing behavior is also found for the condensed quartet component. The proton occupation of the orbit is strongly enhanced relative to the conventional like-particle BCS reference and is driven close to the degeneracy-weighted limit. These results suggest that additional valence neutrons enhance the quartet admixture in the correlated quartet BCS state, while redistributing the fixed proton weight from pair-like configurations to quartet configurations.

    Comments:
    9 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); Atomic Physics (physics.atom-ph); Quantum Physics (quant-ph)
    arXiv:
    2607.15700 [pdf]
    0 citations
  2. 02

    [Submitted on 17 Jul 2026]

    Breakdown of Smooth Shock Solutions in Transient Relativistic Hydrodynamics

    Davi D. de Oliveira🇧🇷 · Gabriel S. Denicol🇧🇷

    In this work, we demonstrate that shock solutions in the Israel-Stewart framework lose regularity once the shock velocity reaches a critical value, and a discontinuity emerges in the solution, which can be interpreted as a second shock wave. This subshock arises as a consequence of the finite speed of information propagation inherent to the Israel-Stewart theory. We then perform numerical simulations to confirm the breakdown of solution continuity. Subsequently, we propose two regularization procedures to extend the domain of continuous shock solutions. The first employs a third-order extension, which introduces new kinetic fields, while the second incorporates a small numerical bulk viscosity. Both methods effectively increase the maximum propagation speed of the Israel-Stewart theory and extend the range over which regular shock solutions exist. Thus, we confirm that this loss of regularity is a direct consequence of the Israel-Stewart framework. These results suggest that Israel-Stewart theory may not provide an adequate description of ultra-relativistic shock waves.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2607.15756 [pdf]
    0 citations
  3. 03

    [Submitted on 17 Jul 2026]

    Spin and orbital scissors modes in Er

    E.B. Balbutsev · I.V. Molodtsova

    Recently, low-energy dipole excitations in Er were investigated via nuclear resonance fluorescence [T. Shizuma {\it et al}, Phys. Rev. C {\bf 113}, 044325 (2026)]. The magnetic dipole strength associated with the nuclear scissors mode was extracted for excitation energies between 2.2 and 3.5 MeV. It was found that the strength distribution is separated into two groups. We interpret this splitting as caused by the spin degrees of freedom instead of the nucleus nonaxiality suggested by authors.

    Comments:
    5 pages, 2 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2607.15885 [pdf]
    0 citations
  4. 04

    [Submitted on 17 Jul 2026]

    The anomalous long lifetime of C revealed by ab initio nuclear lattice EFT

    Teng Wang · Serdar Elhatisari · Xu Feng · Bing-Nan Lu · Ulf-G. Meißner

    The 5730-year half-life of C, the physical basis of radiocarbon dating, is anomalously long compared to typical nuclear-physics expectations. Its origin has remained a subject of debate for many decades. Here we report an \textit{ab initio} nuclear lattice effective field theory (NLEFT) calculation of C decay. Using systematically optimized interactions and transition operators consistently derived from chiral effective field theory, We obtain a result consistent with the Gamow-Teller matrix element measured with the current uncertainty of . We first show that chiral interactions and weak currents beyond leading-order are essential for quenching the GT matrix element to the physical value, among which the optimization of three-nucleon forces is indispensable. We then illustrate that the quenching is deeply rooted in the ground-state structure of N as found in the nuclear shell model, where the competition between - and -wave components exists, sensitive to the interaction employed. The physical N ground state is found to be dominated by -wave configurations, which constitutes the key factor for the quenching. The sensitivity of the decay matrix element to the fine-tuning of low-energy-constants is explored, revealing the prominent role of the -channel two-nucleon contact force and the one-pion-exchange three-nucleon force. This work eliminates the gap between shell-model and \textit{ab initio} studies of C decay, provides a valid and straightforward explanation for the anomalous long lifetime of C, and turns NLEFT into a practical tool for the systematic study of nuclear transitions.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2607.15984 [pdf]
    0 citations

Affiliations

first authorsco-authorsvia INSPIRE