Study of charm production in Z decays
The ALEPH Collaboration
R. Barate - et al.
Laboratoire de Physique des Particules (LAPP), IN2P3-CNRS,
74019 Annecy-le-Vieux Cedex, France
Received: 21 September 1999 / Published online: 8 June 2000 - © Springer-Verlag 2000
The production rates of , , , , , and in decays are measured using the LEP I data sample recorded by the ALEPH detector. The fractional energy spectrum of the is well described as the sum of three contributions: charm hadronisation, b hadron decays and gluon splitting into a pair of heavy quarks. The probability for a c quark to hadronise into a D*+ is found to be . The average fraction of the beam energy carried by mesons in events is measured to be The energy and the hemisphere mass imbalance distributions are simultaneously used to measure the fraction of hadronic Z decays in which a gluon splits to a pair: The ratio of the Vector/(Vector+Pseudoscalar) production rates in charmed mesons is found to be . The fractional decay width of the Z into pairs is determined from the sum of the production rates for various weakly decaying charmed states to be
Copyright Società Italiana di Fisica, Springer-Verlag 2000