Perturbative QCD analysis of B(B→Xlν̄), charm yield 〈nc〉 in B decay, and τ(Λb)/τ(Bd)

We apply perturbative QCD factorization theorems to inclusive heavy hadron decays, and obtain simultaneously a low semileptonic branching ratio B(B→Xlν̄)=10.16%, the average charm yield 〈nc〉=1.17 per B decay, a small lifetime ratio τ(Λb)/τ(Bd)=0.78, and the correct absolute decay widths of the B meson and of the Λb baryon.