Evidence for a Direct Three-Nucleon Pion-Absorption Process

Abstract

Evidence for a three-nucleon absorption mechanism has been observed in $^{3}\mathrm{He}$ for positive and negative pions of 220 MeV/c. The effect shows pure phase-space behavior with integrated cross sections of 3.9\ifmmode\pm\else\textpm\fi{}0.5 mb for ${\ensuremath{\pi}}^{+}$ and 3.7\ifmmode\pm\else\textpm\fi{}0.6 mb for ${\ensuremath{\pi}}^{\ensuremath{-}}$ absorption.