Radiative Pion Capture and the Pion-Nucleus Vertex Function

Abstract

We use the Kroll-Ruderman theorem and the elementary-particle treatment of the nucleus to calculate $s$-wave capture rate of pions by ${\mathrm{He}}^3$ and ${\mathrm{Li}}^6$. The results are compared with previous estimates and experiment. We also use the observed Panofsky ratio to study the $\pi {\mathrm{He}}^3{\mathrm{H}}^3$ vertex function.