Experimental status of semileptonic B decays: Recent results from LEP and comparisons with ϒ(4S) experiments

Abstract Recent analyses of the LEP and ϒ(4 S ) data have better outlined the picture of semileptonic B decays. Results on inclusive and exclusive decay branching fractions and on the extraction of the | V ub | and | V cb | elements of the CKM mixing matrix are discussed, together with some of the still open questions and the sources of model systematics.