Identification of Ground State and Mirror Symmetry Violation with
Phys. Rev. Lett. 137, 102501 – Published 2 September, 2026
DOI: https://doi.org/10.1103/3mqd-58tp
Abstract
The ground state of the three-proton emitter has been identified. Energy correlations between the protons and the residue indicate that its decay is sequential initiated by the emission of a single proton to the ground state of followed by simultaneous emission of two protons to the ground state of , and the derived total decay energy is 4.45(3) MeV. The angular distribution of the proton from the first step indicates that this emission is -wave and only consistent with a spin parity of . This assignment is consistent with state-of-the-art Gamow shell-model calculations. As the ground state of is , the assigned spin parity of its mirror indicates that the pair presents a new case of ground-state mirror symmetry violation (GMSV). Unlike other GMSV cases, which arise solely from either a Coulomb induced shift or deformation effects, the case is generated by differences in the many-body correlations.