Detection of Pion Single Charge Exchange in Zirconium

Abstract

The reaction $^{91}\mathrm{Zr}({\ensuremath{\pi}}^{+},{\ensuremath{\pi}}^{0})^{91}\mathrm{Nb}^{*}$ was observed by detecting the decay proton $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{p}$ from the isobaric analog state $^{91}\mathrm{Nb}^{*}$ in the sequential process $^{91}\mathrm{Zr}({\ensuremath{\pi}}^{+},{\ensuremath{\pi}}^{0}\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{p})^{90}\mathrm{Zr}$. The observed cross section for an incident pion energy of 30 MeV is 1.1 \ifmmode\pm\else\textpm\fi{} 0.8 mb, and is in reasonable agreement with theoretical calculations.