Narrow resonances in the continuum of the unbound nucleus ${}^{15}$F

Abstract

The structure of the unbound ${}^{15}$F nucleus is investigated using the inverse kinematics resonant scattering of a radioactive ${}^{14}$O beam impinging on a CH${}_2$ target. The analysis of ${}^1$H(${}^{14}$O,p)${}^{14}$O and ${}^1$H(${}^{14}$O,2p)${}^{13}$N reactions allowed the confirmation of the previously observed narrow $1/2^{-}$ resonance, near the two-proton decay threshold, and the identification of two new narrow 5/2${}^{-}$ and 3/2${}^{-}$ resonances. The newly observed levels decay by 1p emission to the ground of ${}^{14}$O, and by sequential 2p emission to the ground state (g.s.) of ${}^{13}$N via the $1^{-}$ resonance of ${}^{14}$O. Gamow shell model (GSM) analysis of the experimental data suggests that the wave functions of the 5/2${}^{-}$ and 3/2${}^{-}$ resonances may be collectivized by the continuum coupling to nearby 2p- and 1p- decay channels. The observed excitation function ${}^1$H(${}^{14}$O,p)${}^{14}$O and resonance spectrum in ${}^{15}$F are well reproduced in the unified framework of the GSM.

7 pages, 4 figures