Measurement of the production rate of charm quark pairs from gluons in hadronic Z0 decays

The rate of secondary charm-quark- pair productionhas been measured in 4.4 million hadronicZ0 decays collected by OPAL. By selecting events with three jets and tagging charmed hadronsin the gluon jet candidate using leptons and D⋆± mesons, the average number of secondary charm-quarkpairs per hadronicevent is found to be (3.20 ± 0.21 ± 0.38) ×10−2.