Inclusive lepton production in hadronic events from e/sup +/e/sup -/ annihilation at 29 GeV

Abstract

We have measured the production rates of prompt electrons and muons in hadronic events from e/sup +/e/sup -/ annihilation at 29 GeV. The inclusive rate per hadronic event for leptons with total momenta greater than 2 GeV/c is determined to be (0.033 +- 0.003 +- 0.012) for electrons and (0.037 +- 0.005 +- 0.008) for muons. We measure the longitudinal and transverse momentum spectra of these leptons. The harder transverse momentum spectrum of leptons from bottom and charm quark relative to charm decays allows us to separate the bottom and charm quark contributions to the prompt lepton signal. The longitudinal momentum distributions allow us to study the fragmentation properties of these heavy quarks. For charm quarks we find average semileptonic branching ratios of (6.4 +- 1.3 +- 2.8)% into electrons and (8.1 +- 1.6 +- 1.8)% into muons. For bottom quarks we find average branching ratios of (12.9 +- 2.5 +- 2.0)% into electrons and (12.2 +- 5.0 +- 3.0)% into muons. The fragmentation function for bottom quarks is determined to be peaked at large z with /sub b/ approx. = 0.75. 46 references.