G. Abbiendi et al., Production rates of b(b)over-bar quark pairs from gluons and b(b)over-barb(b)over-bar events in hadronic Z(0) decays, EUR PHY J C, 18(3), 2001, pp. 447-460
The rates are measured per hadronic Z(0) decay for gluon splitting to b (b)
over bar quark pairs, g(b (b) over bar), and of events containing two b (b
) over bar quark pairs, g(4b), using a sample of four-jet events selected f
rom data collected with the OPAL detector. Events with an enhanced signal o
f gluon splitting to b (b) over bar quarks are selected if two of the jets
are close in phase-space and contain detached secondary vertices. For the e
vent sample containing two b (b) over bar quark pairs, three of the four je
ts are required to have a significantly detached secondary vertex. Informat
ion from the event topology is combined in a likelihood fit to extract the
values of g(b (b) over bar) and g(4b), namely
g(b (b) over bar) = (3.07 +/- 0.53(stat) +/- 0.97(syst)) x 10(-3),
g(4b) = (0.36 +/- 0.17(stat) +/- 0.27(syst)) x 10(-3).