Results from an Analysis of Missing Transverse Energy Events in the UA1 Experiment at the CERN p Anti p Collider

摘要

Results from an analysis of missing transverse energy events from a data sample of 715 nb sup -1 in the UA1 experiment at the CERN Proton-Antiproton Collider are presented. A signal of high-transverse-momentum tau-leptons from W decays is observed through their semihadronic decay modes. The measured relative rates of W -> e nu, W -> mu nu, and W -> tau nu provide the first direct tests of e- mu -tau universality of the weak charged couplings at Q sup 2 = m/sub w/ sup 2 . The remaining events that are not clear W -> tau nu candidates are found to be consistent in rate with the expected contributions from Standard Model sources. After accounting for these expected contributions, we obtain the following limits on various possible new physics processes: (1) a mass limit for a fourth-generation charged heavy lepton of m/sub L/ > 41 GeV/c sup 2 (90% CL); (2) a limit on the total number of neutrino species of n/sub nu/ less than or equal to 10 (90% CL); and (3) model-dependent supersymmetric mass limits for squarks and gluinos of m/sub q/ > 70 GeV/c sup 2 and m/sub g/ > 60 GeV/c sup 2 (90% CL), respectively. The rate of events with E/sub T//sup jet/ > 40 GeV and which are not tau candidates is found to be slightly higher than theoretical expectations and may indicate increased activity in Z sup 0 production at large transverse momentum. 18 refs., 13 figs. (ERA citation 13:027066)