Further results on parity conservation in π-μ-e decays

Summary  In a previous note (1) the present authors gave some preliminary results on the angular distribution of the decay products in π-μ-e decays. This research was suggested byLee andYang (2) to verify parity conservation in weak interactions. In fact, if parity conservation is violated in both processes (π-μ and μ-e decays) the angular distribution of the electron with respect to the line of motion of the μ-meson in the system in which the π is at rest, is expected to follow the lawf(ω)=const × (1+α cos ω). On a total of 1028 events we obtain now α=− 0.222±0.067. The probability of α being zero (isotropic distribution) is found to be ∼ 3 · 10−3. All the decays have been observed in plates exposed to cosmic rays.