A study of charm and anti-charm production in beauty decays with the OPAL detector at LEP

摘要

The branching ratio of beauty hadrons to final states containing two charm hadrons, Br(b ( o mathrm{Dar{D}X}), has been measured using an inclusive method in hadronic Z0 decays with the OPAL detector at LEP. The impact parameter significance of tracks opposite tagged b-jets is used to differentiate b ( o mathrm{Dar{D}X}) decays from other decays. The result is ( mathrm{Br(b} o mathrm{Dar{D}X}) = (10.0 pm 3.2 (mathrm{stat.})^{+2.4}_{-2.9}(mathrm{det.})^{+10.4}_{-9.0} (mathrm{phys.}))%,) where “det.” is the systematic uncertainty due to the modelling of the detector, and “({ m phys.})” is the systematic uncertainty due to the modelling of the underlying physics. Using this result, the average number of charm plus anti-charm quarks produced in a beauty quark decay, nc, is found to be 1.12 + 0.11-0.10.