Spectator effects and lifetimes of heavy hadrons

Abstract

We present a calculation of subleading $1/{m}_{b}$ corrections to spectator effects in the ratios of beauty hadron lifetimes in heavy-quark expansion. We find that these effects are sizable and should be taken into account in systematic analyses of heavy hadron lifetimes. In particular, the inclusion of $1/{m}_{b}$ corrections brings into agreement the theoretical predictions and experimental observations of the ratio of lifetimes of ${\ensuremath{\Lambda}}_{b}$ baryon and ${B}_{d}$ meson. We obtain $\ensuremath{\tau}({B}_{u})/\ensuremath{\tau}({B}_{d})=1.06\ifmmode\pm\else\textpm\fi{}0.02$, $\ensuremath{\tau}({B}_{s})/\ensuremath{\tau}({B}_{d})=1.00\ifmmode\pm\else\textpm\fi{}0.01$, $\ensuremath{\tau}({\ensuremath{\Lambda}}_{b})/\ensuremath{\tau}({B}_{d})=0.86\ifmmode\pm\else\textpm\fi{}0.05$.