Measurement of the B0-meson lifetime

We report a measurement of the lifetime of the {ital B}{sup 0} meson based upon 29-GeV {ital e}{sup +}{ital e}{sup {minus}} annihilation data taken with the Mark II detector at the SLAC storage ring PEP. The {ital B}{sup 0} mesons are tagged by their decays into {ital D}{sup *{minus}}{ital e}{sup +}{nu} and {ital D}{sup *{minus}}{mu}{sup +}{nu}, where the {ital D}{sup *{minus}} is tagged by its decay into {pi}{sup {minus}}{ital {bar D}}{sup 0}. We reconstruct the decay vertices of 15 {ital B}{sup 0}-meson candidates and measure the {ital B}{sup 0} lifetime to be 1.20{sup +0.52}{sub {minus}0.36}{sup +0.16}{sub 0.14} psec.