The Absorption of Slowπ−Mesons in Deuterium

The possible mechanisms for absorption of ${\pi }^{-}$ mesons in deuterium are considered. A phenomenological treatment of the simple "neutron absorption" enables one to calculate the competition between the processes independently of the value of the ${\pi }^{-}$ nucleon coupling constant. It is found that various meson theories for the charged meson lead to markedly different predictions for the fraction of events leading to gamma-ray emission. The results are compared with experiment and lead to the conclusion that the charged meson is either pseudoscalar or pseudovector. Comparison with the (${\pi }^0:\gamma$) ratio from the absorption in hydrogen indicates that if the charged meson is pseudoscalar the neutral meson is also pseudoscalar.