Single Particle Strengths and Mirror States in ${}^{15}$N${-}^{15}$O below 12.0 MeV

Abstract

New ${}^{14}$N(d,p) angular distribution data were taken at a deuteron bombarding energy of 16 MeV to locate all narrow single particle neutron states up to 15 MeV in excitation. A new shell model calculation is able to reproduce all levels in ${}^{15}$N up to 11.5 MeV and is used to characterize a narrow single particle level at 11.236 MeV and to provide a map of the single particle strengths. The known levels in ${}^{15}$N are then used to determine their mirrors in the lesser known nucleus ${}^{15}$O. The 2s${}_{1/2}$ and 1d${}_{5/2}$ single particle centroid energies are determined for the ${}^{15}$N${-}^{15}$O mirror pair as: ${}^{15}$N $({\text{2s}}_{1/2})=8.08$ MeV, ${}^{15}$O $({\text{2s}}_{1/2})=7.43$ MeV, ${}^{15}$N $({\text{1d}}_{5/2})=7.97$ MeV, and ${}^{15}$O $({\text{1d}}_{5/2})=7.47$ MeV. These results confirm the degeneracy of these orbits and that the ${}^{15}$N${-}^{15}$O nuclei are where the transition between the ${\text{2s}}_{1/2}$ lying below the ${\text{1d}}_{5/2}$ to lying above it, takes place. The ${\text{1d}}_{3/2}$ single particle strength is estimated to be centered around 13 MeV in these nuclei.

9 pages, 7 figures, submitted to Physical Review C for publication