A measurement of the inclusive semileptonic decay fraction of charmed hadrons

Abstract Using the ARGUS detector at the DORIS-II storage ringat DESY, we have measured the inclusive semileptonic branching ratio of charmed hadrons produced in e + e − annihilition at =10 GeV to be BR(c→ev e X)=(9.8±0.9± 0.5 0.6 )% and BR(c→ μv μ X)=(8.6±1.7± 0.7 0.8 )%.