Preasymptotic effects in beauty decays

Abstract

Large preasymptotic effects in beauty decays have been found using heavy-quark and SU(3) symmetry, as well as experimental data on charmed hyperons. Contrary to rather uniform beauty-meson lifetimes, a much larger spread of beauty-baryon lifetimes is predicted. However, it is highly unlikely that, theoretically, the $ τ(Λ_b)/τ(B_d^0) $ ratio, which at present deviates more than $1σ$ from the experimental result, can be lowered below 0.9.