2025/12/08 by Wang, J. L., Xie, M. R., Li, K. H. +4
Physics and Astronomy · #Nuclear physics research studies #Quantum Chromodynamics and Particle Interactions #Astronomical and nuclear sciences
paper · doi:10.48550/arxiv.2512.07594
Proton-rich nuclei beyond the proton drip line are of great interest in nuclear structure physics, due to exotic phenomena such as proton emissions and the Thomas-Ehrman shift (TES). In this work, we employ the Gamow shell model (GSM) to investigate the structure and decay of 20Si, a candidate for six-proton (6p) emission, which can be produced via two-neutron knockout from the drip line nucleus 22Si. We predict that its ground state decays via 6p emission to the ground state of 14O, with a decay energy E6p = 10.125 MeV and a width of 371~keV. A 2+ state is predicted at 1.7 MeV, comparable with that in 18Mg, indicating the disappearance of the Z=14 magic number in 20Si. Instead, analyses of the many-body configurations and the average occupancies of the mirror states suggest the presence of dynamic TES in low-lying states of 19Al/19C and 20Si/20C. Further evidence is provided by analyzing the contributions of different components of the GSM Hamiltonian. Moreover, this study offers the first theoretical description of 20Si and guidance for future experiments.