MULTIPLICITY DISTRIBUTIONS OF GLUON AND QUARK JETS AND A TEST OF QCD ANALYTIC CALCULATIONS

Gluon jets are identified in e(+)e(-) hadronic annihilation events by tagging two quark jets in the same hemisphere of an event. The gluon j et is defined inclusively as all the particles in the opposite hemisph ere. Gluon jets defined in this manner have a close correspondence to gluon jets as they are defined for analytic calculations, and are almo st independent of a jet finding algorithm. The mean and first few high er moments of the gluon jet charged particle multiplicity distribution are compared to the analogous results found for light quark (uds) jet s, also defined inclusively. Large differences are observed between th e mean, skew and curtosis values of the gluon and quark jets, but not between their dispersions. The cumulant factorial moments of the distr ibutions are also measured, and are used to test the predictions of QC D analytic calculations. A calculation which includes next-to-next-to- leading order corrections and energy conservation is observed to provi de a much improved description of the separated gluon and quark jet cu mulant moments compared to a next-to-leading order calculation without energy conservation. There is good quantitative agreement between the data and calculations for the ratios of the cumulant moments between gluon and quark jets. The data sample used is the LEP-1 sample of the OPAL experiment at LEP.