Interaction of Negative Pions with Mercury

Abstract

Radiochemical separation of expected fission products from mercury irradiated with 122-Mev ${\pi }^{-}$ mesons demonstrates that fission occurs. The fission products are distributed in yield similar to those from the fission of mercury by high-energy neutrons. The branching ratio for meson fission is about 0.5 percent. Thallium activities found in the meson-irradiated mercury are explained as produced by secondary fast protons.