B c and $$b\bar bc\bar c$$ at theZ 0-boson pole

Abstract

The cross-section for the production of\(b\bar bc\bar c\) quarks ine+e− annihilation, that proves to be at a level of\(\sigma (e^ + e^ - \to b\bar bc\bar c)/\sigma (e^ + e^ - \to b\bar b) \sim 10^{ - 2} \) for\(\sqrt s = M_Z \) is calculated within the frames of the QCD perturbation theory. The cross sections for the associated production of 1S-and 2S-wave states ofBc-meson in the reaction\(e^ + e^ - \to B_c b\bar c\) were calculated in the nonrelativistic model of a heavy quarkonium. The number ofΛbc-hyperons to be expected at LEP is estimated on the basis of the assumption on quark-hadron duality.