Spectroscopy of excited states of unbound nuclei ${}^{30}$Ar and ${}^{29}$Cl

Abstract

Several states of proton-unbound isotopes ${}^{30}$Ar and ${}^{29}$Cl were investigated by measuring their in-flight decay products, ${}^{28}$S+proton+proton and ${}^{28}$S+proton, respectively. A refined analysis of ${}^{28}$S-proton angular correlations indicates that the ground state of ${}^{30}$Ar is located at $2.45_{-0.10}^{+0.05}$ MeV above the two-proton emission threshold. The theoretical investigation of the ${}^{30}$Ar ground state decay demonstrates that its mechanism has the transition dynamics with a surprisingly strong sensitivity of the correlation patterns of the decay products to the two-proton decay energy of the ${}^{30}$Ar ground state and the one-proton decay energy as well as the one-proton decay width of the ${}^{29}$Cl ground state. The comparison of the experimental ${}^{28}$S-proton angular correlations with those resulting from Monte Carlo simulations of the detector response illustrates that other observed ${}^{30}$Ar excited states decay by sequential emission of protons via intermediate resonances in ${}^{29}$Cl. Based on the findings, the decay schemes of the observed states in ${}^{30}$Ar and ${}^{29}$Cl were constructed. For calibration purposes and for checking the performance of the experimental setup, decays of the previously-known states of a two-proton emitter ${}^{19}$Mg were remeasured. Evidences for one new excited state in ${}^{19}$Mg and two unknown states in ${}^{18}$Na were found.

arXiv comment17 pages, 16 figures

References in corpus (4)

• Radioactive decays at limits of nuclear stability
• First observation of 54Zn and its decay by two-proton emission
• The landscape of two-proton radioactivity
• Transition from direct to sequential two-proton decay in $s$-$d$ shell nuclei

Cited by in corpus (7)

• Recent Progress in Two-proton Radioactivity
• Towards the Limits of Existence of Nuclear Structure: Observation and First spectroscopy of the Isotope ${}^{31}$K by measuring its three-proton Decay
• Deep excursion beyond the proton dripline. I. Argon and chlorine isotope chains
• Observation and spectroscopy of proton-unbound nucleus ${}^{21}$Al
• Mirror Symmetry Breaking Disclosed in the Decay of Three-Proton Emitter 20Al
• Deep excursion beyond the proton dripline. II. Toward the limits of existence of nuclear structure
• Pauli-principle driven correlations in four-neutron nuclear decays