Measurements of Gamow-Teller strength distributions in masses 13 and 15.

Abstract

The differenctial cross section and the transverse spin-flip probability have been measured for the dominant transitions in $^{13}\mathrm{C}$(p,n${)\mathrm{}}^{13}$N and $^{15}$N(p,n${)\mathrm{}}^{15}$O at ${\mathrm{E}}_{\mathrm{p}}$=160 MeV. The Gamow-Teller transition strengths deduced from the data show that the major ${(1/2)}^{\mathrm{\ensuremath{-}}}$\ensuremath{\rightarrow}${(3/2)}^{\mathrm{\ensuremath{-}}}$ transitions are strongly quenched relative to the ${(1/2)}^{\mathrm{\ensuremath{-}}}$\ensuremath{\rightarrow}${(1/2)}^{\mathrm{\ensuremath{-}}}$ mirror transitions, in strong disagreement with simple shell-model expectations.