Measurement Of Anomalous Dimuons Produced In Electron Positron Annihilations PDF Download

Results of studies of anomalous electron-muon and electron-hadron events produced in electron-positron annihilation are presented. The data for this work were obtained with a lead-glass counter system, which was added to one octant of the Stanford Linear Accelerator Center-Lawrence Berkeley Laboratory magnetic detector at the electron-positron storage ring SPEAR. The lead-glass counter system provides good electron identification for part of the magnetic detector. The events under study have two detected charged particles and any number of detected photons. One detected charged particle is identified as an electron in the lead-glass counter system. The other detected charged particle is identified as a muon or hadron in the magnetic detector. Anomalous events are events which are not subject to conventional explanations; examples of conventional explanations are misidentification of particles or the decay of ordinary or strange hadrons. These data confirm previous observations of anomalous lepton production at SPEAR and DESY. The data corrected for charm background are consistent with heavy lepton production and decay. The branching ratio for the heavy lepton to decay into an electron and two neutrinos was measured to be 0.21 +- 0.05. The branching ratio for the heavy lepton to decay into one charged hadron, one neutrino and any number of photons was measured to be 0.28 +- 0.13. They are consistent with the theoretical values within the errors.