Measurement of the multiplicity of charm quark pairs from gluons in hadronic Z0 Decays

We have measured the multiplicity of charm quark pairs arising from gluon splitting in a sample of about 3.5 million hadronic Z0 decays. By selecting a 3-jet event topology and tagging charmed hadrons in the lowest energy jet using leptons, we established a signature of heavy quark pair production from gluons. The average number of gluons splitting into a cc pair per hadronic event was measured to be ng→cc=(2.27±0.28±0.41) × 10−2.