Measurement of f(c -> D^*+ X), f(b -> D^*+ X) and Gamma_cc(bar)/Gamma_had using D^*+/- Mesons

TL;DR

This paper measures the production rates of D^*+/- mesons from charm and bottom quarks in Z^0 decays at LEP, providing key data on hadronization fractions and the cc̄ event fraction in hadronic decays.

Contribution

It presents new measurements of charm and bottom quark hadronization fractions into D^*+/- mesons and the cc̄ event fraction in Z^0 decays using LEP data and advanced tagging methods.

Findings

f(b -> D^*+ X) = 0.173 +/- 0.016 +/- 0.012

f(c -> D^*+ X) = 0.222 +/- 0.014 +/- 0.014

Gamma_cc(bar)/Gamma_had = 0.180 +/- 0.011 +/- 0.012 +/- 0.006

Abstract

The production rates of D^*+/- mesons in charm and bottom events at centre-of-mass energies of about 91 GeV and the partial width of primary cc(bar) pairs in hadronic Z^0 decays have been measured at LEP using almost 4.4 million hadronic Z^0 decays collected with the OPAL detector between 1990 and 1995. Using a combination of several charm quark tagging methods based on fully and partially reconstructed D^*+/- mesons, and a bottom tag based on identified muons and electrons, the hadronisation fractions of charm and bottom quarks into D^*+/- mesons have been found to be: f(b -> D^*+ X) = 0.173 +/- 0.016 +/- 0.012 and f(c -> D^*+ X) = 0.222 +/- 0.014 +/- 0.014 The fraction of cc(bar) events in hadronic Z^0 decays, Gamma_cc(bar)/Gamma_had = Gamma(Z^0 -> cc(bar))/Gamma(Z^0 -> hadrons), is determined to be Gamma_cc(bar)/Gamma_had = 0.180 +/- 0.011 +/- 0.012 +/- 0.006 In all cases the first error is statistical, and the second one systematic. The last error quoted for Gamma_cc(bar)/Gamma_had is due to external branching ratios.