Lifetime ratios of beauty hadrons at the next-to-leading order in QCD

Abstract

We compute the next-to-leading order QCD corrections to spectator effects in the lifetime ratios of beauty hadrons. With respect to previous calculations, we take into account the non-vanishing value of the charm quark mass. We obtain the predictions τ( B +)/ τ( B d )=1.06±0.02, τ( B s )/ τ( B d )=1.00±0.01 and τ( Λ b )/ τ( B d )=0.90±0.05, in good agreement with the experimental results. In the case of τ( B s )/ τ( B d ) and τ( Λ b )/ τ( B d ), however, some contributions, which either vanish in the vacuum insertion approximation or represent a pure NLO correction, have not been determined yet.