**16**, 597-611

DOI 10.1007/s100520000421

## Study of charm production in Z decays

**The ALEPH Collaboration
R. Barate - et al.**

Laboratoire de Physique des Particules (LAPP), IN^{2}P^{3}-CNRS,
74019 Annecy-le-Vieux Cedex, France

Received: 21 September 1999 / Published online: 8 June 2000 - © Springer-Verlag 2000

**Abstract**

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