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 if mL± - mνL > 10 GeV. If L± decays through lepton flavour mixing into a massless neutrino νℓ and W*±, the lower limit on mL± was determined to be 63.9 GeV at 95% C.L.
Original language | English |
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Pages (from-to) | 433-444 |
Number of pages | 12 |
Journal | Physics Letters B |
Volume | 385 |
Issue number | 1-4 |
DOIs | |
State | Published - Sep 26 1996 |
Externally published | Yes |
Funding
We particularly wish to thank the SL Division for their efficient operation of the LEP accelerator and for their continuing close cooperationw ith our experimental group. In addition to the support staff at our own institutions we are pleasedt o acknowledget he Departmento f Energy, USA, National Science Foundation, USA, Particle Physics and Astronomy Research Council, UK Natural Sciences and Engineering Research Council, Canada, Israel Ministry of Science, Israel Science Foundation, administeredb y the Israel Academy of Science and Humanities, Minerva Gesellschaft, Japanese Ministry of Education, Science and Culture (the Monbusho) and a grant under the Monbusho International Science Research Program, German Israeli Bi-national Science Foundation (GIF), Direction des Sciences de la Mat&e du Commissariat a 1’Energie Atomique, France, Bundesministerium fur Bildung, Wissenschaft, Forschung und Technologie, Germany, National ResearchC ouncil of Canada, Hungarian Foundation for Scientific Research,G TKA T-016660, and OTKA F-015089.
Funders | Funder number |
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Direction des Sciences de la Mat&e du Commissariat a 1’Energie Atomique, France, Bundesministerium fur Bildung, Wissenschaft, Forschung und Technologie | |
German Israeli Bi-national Science Foundation | |
Hungarian Foundation for Scientific Research | G TKA T-016660, OTKA F-015089 |
Israel Ministry of Science, Israel Science Foundation | |
Minerva Gesellschaft | |
National ResearchC ouncil of Canada | |
National Science Foundation | |
U.S. Department of Energy | |
Natural Sciences and Engineering Research Council of Canada | |
Ministry of Education, Culture, Sports, Science and Technology | |
Israel Academy of Sciences and Humanities |