Angular momentum selection rule and theBe9(π+, p)Be8reaction at 50 MeV

Abstract

Angular distributions have been measured at 50 MeV for the $^{9}\mathrm{Be}({\ensuremath{\pi}}^{+}, p)^{8}\mathrm{Be}$ reaction leading to the ${0}^{+}$, ${2}^{+}$, and ${4}^{+}$ states of $^{8}\mathrm{Be}$. An angular momentum selection rule is considered in order to account for the preferential excitation of high spin states. Two-step processes in the framework of the distorted-wave Born approximation and momentum sharing in the two-nucleon model are also discussed.NUCLEAR REACTIONS $^{9}\mathrm{Be}({\ensuremath{\pi}}^{+}, p)^{8}\mathrm{Be}$, ${E}_{\ensuremath{\pi}}=50$ MeV; measured $\ensuremath{\sigma}(\ensuremath{\theta})$; reaction mechanism discussed.