Search for massive neutrinos in the decay pi -> e nu

Evidence of massive neutrinos in the pi(+) -> e(+)nu decay spectrum was sought with the background pi(+) -> mu(+) -> e(+) decay chain highly suppressed. Upper limits (90% C. L.) on the neutrino mixing matrix element vertical bar U(ei)vertical bar(2) in the neutrino mass region 60-129 MeV/c(2) were set at the level of 10(-8).