Spectroscopic study of the exotic nucleusP25

Abstract

Motivated by the importance of 25 P for the two-proton decay of 26 S and for searches of the mirror analog of the island of inversion near N = 16, we present the first predictions for the spectroscopy of the exotic isotope 25 P obtained in the shell model, a potential model, and a microscopic-cluster model. All models predict 25 P to be unbound, with an energy in the range 0.78-1.03 MeV, which favors previous mass systematics over more recent revisions. We show that 25 P possesses a rich low-lying spectrum that should be accessible by experimental studies. All of the predicted states below 7 MeV, except one, are narrow. Many of them are built on the excited-core states of 24 Si for which the Coulomb barrier is raised. For decays into the 24 Si(g.s.) + p channel we determined the proton widths based on their link to the asymptotic normalization coefficients (ANCs) of their mirror analogs in 25 Ne. We determine these ANCs from the analysis of the transfer reaction 24 Ne(d,p) 25 Ne. The proton widths for decay into excited-state channels are obtained in model calculations. The only broad state is the intruder 3/2 − , the mirror analog of which has been recently observed in 25 Ne. The 25 P(3/2 − ) energy is lower than that in 25 Ne, suggesting that the island of inversion may persist on the proton-rich side. All excited states of 25 P have at least two decay modes and are expected to populate variously the 2 + 1,2 and 4 + states in 24 Si, which then decay electromagnetically.

Low-lying single-particle structure of 17C and the N = 14 sub-shell closure

“…ANC of the normalized bound-state wave function used in the reaction calculation, provided that the reaction is peripheral. In addition to providing the normalization of the wave functions outside of the core-particle potential, neutron ANCs can be used to predict the widths of resonances in the unbound proton-rich mirror nucleus [62], which for 17 C is the potential three-proton emitter 17 Na [48]. The peripherality of the present reaction was checked by studying the dependence of the ANC on the geometric parameters of the neutron binding potential.…”