A Measurement of n(g->cc) using D* Mesons

At LEP I charm quarks are mainly produced directly from the Z decay or via the decay of bottom hadrons. A third source is a primary quark radiating a hard gluon which then splits into a ccbar pair. This process is predicted to occur in approximately 1.5% of all hadronic Z decays. The data collected with the ALEPH detector from 1991 to 1995 have been investigated to look for this process. Charm quarks are tagged by reconstructing D*+- mesons via their decay D*+ -> D0 pi+ -> K- pi+ pi+. D*'s from gluon splitting are mostly found in a high--mass hemisphere. Fitting the hemisphere mass distribution for events with reconstructed D*'s, the contribution of g -> D* is extracted. The average multiplicity n(g->cc) of charm quark pairs from gluon splitting in hadronic Z decays is measured.