The probability P(c --> D*(+)) that a charm quark fragments into a D*+ meso
n and the c --> l(+) semileptonic branching fraction were measured in Z(0)
decay into c (c) over bar events.
From the analysis of 3.5 Million Z(0) events collected from 1992 to 1995, a
sample of charm meson decays with 81% c (c) over bar purity was selected.
The product of the c --> D*(+) fragmentation probability times the D*(+) --
> D(0)pi(+) branching fraction was measured to be:
P(c --> D*(+)).BR(D*(+) --> D(0)pi(+)) = 0.174 +/- 0.010(stat) +/- 0.004(sy
st).
Using the world averaged value for BR(D*+ --> D(0)pi(+)), the fragmentation
probability is inferred:
P(c --> D*(+)) = 0.255 +/- 0.015(stat) +/- 0.006(syst) +/- 0.005(syst.BR).
From the same sample, 1828 +/- 51 identified leptons in the opposite hemisp
here were selected. From this sample, the charm semileptonic branching frac
tion was measured to be:
BR(c --> l(+)) = 0.0958 +/- 0.0042(stat) +/- 0.0028(syst).