ESTIMATE OF THE NEUTRAL $pi$-MESON LIFETIME

The lifetime of pi /sup 0/ was determined by analyzing K+ decays at rest in emulsions. Events were selected in which the K pi /sub 2/ mode, K/sup +/ -- pi /sup l/ + pi /sup o/, was followed by the decay of the pi /sup o/ meson to give an electron pair. Both the velocity and direction of flight of the pi / sup 0/ were determined by the kinematics of the K/sup +/ decay, and the presence of the electron pair allowed the point of decay of the pi /sup 0/ to be found. The results of 26 pair events were analyzed. The value obtained for the mean lifetime is (3.2 ) x 10/sup -16/ sec. (M.C.G.)