Memo on Extracting |V(cb)| and |V(ub)/V(cb)| from semileptonic B decays

Abstract

Heavy Quark Expansions for semileptonic decays of beauty hadrons are briefly reviewed. I analyze how $|V(cb)|$ can be extracted from the semileptonic width of $B$ mesons, the average semileptonic width of all weakly decaying beauty hadrons and from $B\text{ra}l\nu D^{\ast }$ at zero recoil. Special attention is paid to present theoretical uncertainties (including correlations among them) and on how to reduce them in the future. Finally I will comment on theoretical uncertainties in $|V(ub)/V(cb)|$.

Comments: Contributed to the Informal Workshop on the Derivation of |V(cb)| and |V(ub)|, CERN, May 28 - June 2, 1999, 19 pages, LATEX