G. Abbiendi et al., A measurement of the product branching ratio f(b -> Lambda(b)) center dot BR(Lambda(b) -> Lambda X) in Z(0) decays, EUR PHY J C, 9(1), 1999, pp. 1-9
The product branching ratio, f(b --> Lambda(b)) . BR(Lambda(b) --> Lambda X
), where Lambda(b) denotes any weakly-decaying b-baryon, has been measured
using the OPAL detector at LEP. Lambda(b)'s are selected by the presence of
energetic Lambda particles in bottom events tagged by the presence of disp
laced secondary vertices. A fit to the moments of the Lambda particles sepa
rates signal from B meson and fragmentation backgrounds. The measured produ
ct branching ratio is
f(b --> Lambda(b)) . BR(Lambda(b) --> Lambda X) = (2.67) +/- 0.38(stat)(-0.
60)(+0.67)(sys))%.
Combined with a previous OPAL measurement, one obtains
f(b --> Lambda(b)) . BR(Lambda(b) --> Lambda X) = (3.50) +/- 0.32(stat) +/-
0.35(sys))%.