Searches for unstable neutral leptons in low-multiplicity events from electron-positron annihilation

Upper limits are given on the production of unstable neutral leptons in electron-positron annihilation at 29 GeV. The searches use selected two- and four-charged-particle events and are most sensitive to neutral-lepton masses of the order of 1 GeV/c2 and smaller. However, results are given for masses up to 14 GeV/c2. © 1985 The American Physical Society.