Theoretical status of the lifetime predictions: $(\Delta \Gamma/ \Gamma)_{B_s}, \tau_{B^+}/\tau_{B_d}$ and $\tau_{\Lambda_b}/\tau_{B_d}$

Abstract

We give a review of the theoretical status of the lifetime predictions in the standard model. In case of $(\Delta \Gamma/ \Gamma)_{B_s}$ we are already in a rather advanced stage. We obtain $(\Delta\Gamma/\Gamma)_{B_s}=(9.3^{+3.4}_{-4.6})%$. It seems to be difficult to improve these errors substantially. In addition now some experimental results are available. For $\tau_{B^+}/\tau_{B_d}$ and $\tau_{\Lambda_b} / \tau_{B_d}$ the theoretical status is much less advanced and the discrepancy between experiment and theory still remains. We conclude with a what-to-do-list for theorists.