Perturbative QCD analysis of $B(B\to Xl\barν)$, charm yield $<n_c>$ in B decay, and $τ(Λ_b)/τ(B_d)$

Abstract

We apply perturbative QCD factorization theorems to inclusive heavy hadron decays, and obtain simultaneously a low semileptonic branching ratio $B(B\to Xl\barν)=10.16%$, the average charm yield $<n_c>=1.17$ per $B$ decay, a small lifetime ratio $τ(Λ_b)/τ(B_d)=0.78$, and the correct absolute decay widths of the $B$ meson and of the $Λ_b$ baryon.