Elsevier

Physics Letters B

Volume 385, Issues 1–4, 26 September 1996, Pages 433-444
Physics Letters B

Search for unstable neutral and charged heavy leptons in e+e collisions at s=130 and 136 GeV

https://doi.org/10.1016/0370-2693(96)00963-XGet rights and content

Abstract

Searches for unstable neutral and charged heavy leptons (L0, L±) have been performed using a data sample of 2.6 pb−1 at a centre-of-mass energy of s=130 GeV and 2.6 pb−1 at 136 GeV collected with the OPAL detector at LEP during November 1995. No candidate event was observed. If an unstable Dirac neutral heavy lepton L0 decays only into eW, μW or τW, the lower limits on its mass at 95% C.L. are 62.5 GeV, 63.0 GeV and 57.4 GeV, respectively. The limits are modified for a Majorana L0 to 51.4 GeV, 52.2 GeV and 44.2 GeV, respectively. For charged heavy leptons, a lower mass limit of 64.5 GeV at 95% C.L. was obtained, if L± decays into a stable heavy neutrino νl and W∗±, and ml± − mνl > 10 GeV. If L± decays through lepton flavour mixing into a massless neutrino ν and W∗±, the lower limit on ml± was determined to be 63.9 GeV at 95% C.L.

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  • Cited by (0)

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