Gamow shell model predictions for six-proton unbound nucleus $^{20}$Si

Fuente: arXiv
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Main Authors: Wang, J. L., Xie, M. R., Li, K. H., Wang, P. Y., Michel, N., Yuan, Q., Li, J. G.
Format: Preprint
Published: 2025
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author Wang, J. L.
Xie, M. R.
Li, K. H.
Wang, P. Y.
Michel, N.
Yuan, Q.
Li, J. G.
author_facet Wang, J. L.
Xie, M. R.
Li, K. H.
Wang, P. Y.
Michel, N.
Yuan, Q.
Li, J. G.
contents 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 $^{20}$Si, a candidate for six-proton (6$p$) emission, which can be produced via two-neutron knockout from the drip line nucleus $^{22}$Si. We predict that its ground state decays via $6p$ emission to the ground state of $^{14}$O, with a decay energy $E_{6p} = 10.125$ MeV and a width of 371~keV. A $2^+$ state is predicted at 1.7 MeV, comparable with that in $^{18}$Mg, indicating the disappearance of the $Z=14$ magic number in $^{20}$Si. 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 $^{19}$Al/$^{19}$C and $^{20}$Si/$^{20}$C. Further evidence is provided by analyzing the contributions of different components of the GSM Hamiltonian. Moreover, this study offers the first theoretical description of $^{20}$Si and guidance for future experiments.
format Preprint
id arxiv_https___arxiv_org_abs_2512_07594
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Gamow shell model predictions for six-proton unbound nucleus $^{20}$Si
Wang, J. L.
Xie, M. R.
Li, K. H.
Wang, P. Y.
Michel, N.
Yuan, Q.
Li, J. G.
Nuclear Theory
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 $^{20}$Si, a candidate for six-proton (6$p$) emission, which can be produced via two-neutron knockout from the drip line nucleus $^{22}$Si. We predict that its ground state decays via $6p$ emission to the ground state of $^{14}$O, with a decay energy $E_{6p} = 10.125$ MeV and a width of 371~keV. A $2^+$ state is predicted at 1.7 MeV, comparable with that in $^{18}$Mg, indicating the disappearance of the $Z=14$ magic number in $^{20}$Si. 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 $^{19}$Al/$^{19}$C and $^{20}$Si/$^{20}$C. Further evidence is provided by analyzing the contributions of different components of the GSM Hamiltonian. Moreover, this study offers the first theoretical description of $^{20}$Si and guidance for future experiments.
title Gamow shell model predictions for six-proton unbound nucleus $^{20}$Si
topic Nuclear Theory
url https://arxiv.org/abs/2512.07594