Measurement of the Semileptonic Branching Ratio of Charm Hadrons Produced in Z to ccbar Decays

TL;DR

This paper measures the semileptonic branching ratios of charm hadrons produced in Z to ccbar decays using a large dataset from the OPAL detector, providing precise experimental results.

Contribution

It presents the first precise measurement of charm hadron semileptonic branching fractions in Z decays using a novel charm-enriched sample selection method.

Findings

B(c to e) = 0.103 +-0.009 +0.009 -0.008

B(c to mu) = 0.090 +-0.007 +0.007 -0.006

Inclusive B(c to l) = 0.095 +-0.006 +0.007 -0.006

Abstract

The inclusive charm hadron semileptonic branching fractions B(c to e) and B(c to mu) in Z to ccbar events have been determined using 4.4 million hadronic Z decays collected with the OPAL detector at LEP. A charm-enriched sample is obtained by selecting events with reconstructed D*+- mesons. Using leptons found in the hemisphere opposite that of the D*+- mesons, the semileptonic branching fractions of charm hadrons are measured to be B(c to e) = 0.103 +-0.009 +0.009 -0.008 and B(c to mu) = 0.090 +-0.007 +0.007 -0.006 where the first errors are in each case statistical and the others systematic. Combining these measurements, an inclusive semileptonic branching fraction of charm hadrons of B(c to l) = 0.095 +-0.006 +0.007 -0.006 is obtained.