Study of inclusive muon production in e+e- annihilation in the center of mass energy range 12 to 31.6 GeV

This dissertation describes an experiment which measured the inclusive production of muons with momenta greater than 1.6 GeV/c in multihadron events in e+e- interactions in the center of mass energy range 12.0 to 31.6 GeV. The experiment was performed at the positron-electron storage ring PETRA at the Deutsches Elektronen-Synchrotron Lab in Hamburg, West Germany. The apparatus used was the PLUTO detector which is a general-purpose magnetic detector with essentially complete coverage for charged particles, photons and leptons. Muon identification was achieved by an approximately one meter thick mostly steel absorber, with arrays of planar drift chambers outside the absorber to detect penetrating particles. In the center of mass energy range 12.0 to 31.6 GeV, the measured inclusive muon production cross section is found to be consistent with a source of muons coming from semi-muonic decay of charm and bottom mesons produced in e+e- annihilation. The larger muon production cross section expected from production and semi-muonic decay of top mesons in the standard model is not observed. The momentum spectrum of the muons was also measured for momenta greater than 1.6 GeV/C and is found to agree with predictions of the charm and bottom decay model. A search for a new charged lepton heavier than the tau was also performed. In the center of mass energy range 29.9 to 31.6 GeV, no multihadron event with an isolated muon which can be attributed to the production and muonic decay of a new heavy lepton was found. A new charged sequential heavy lepton in the mass range 7 to 14 GeV/c2 is excluded at 95% CL