K. Ackerstaff et al., MEASUREMENT OF THE SEMILEPTONIC BRANCHING FRACTION OF INCLUSIVE B-BARYON DECAYS TO LAMBDA, Zeitschrift fur Physik. C, Particles and fields, 74(3), 1997, pp. 423-435
We present the first measurement of the ratio R-Lambda l defined as R-
Lambda l = BR(Lambda(b) --> Lambda lX)/BR(Lambda(b) --> Lambda X) wher
e Lambda(b) denotes all weakly decaying b baryons and l represents the
average of electrons and muons. Using all hadronic Z(0) decay events
collected with the OPAL detector near the Z(0) resonance, we measure R
-Lambda l = (7.0 +/- 1.2 +/- 0.7)%. We also measure f(b --> Lambda(b))
.BR(Lambda(b) --> Lambda X) = (3.93 +/- 0.46 +/- 0.37)%, f(b --> B).BR
(B --> Lambda X) = (1.94 +/- 0.28 +/- 0.24)%, and BR(b --> Lambda X) =
(5.87 +/- 0.46 +/- 0.48)%. In all cases, the uncertainties shown an s
tatistical and systematic. respectively.