Lifetimes and oscillations of heavy mesons

Abstract

We review the theoretical status of the lifetime ratios ${\tau }_{B^{+}}/{\tau }_{B_d}$ and ${\tau }_{B_s}/{\tau }_{B_d}$ and of the mixing quantities $\Delta M_s$, $\Delta {\Gamma }_s$ and ${\varphi }_s$. We show that the ratio $\Delta {\Gamma }_s/\Delta M_s$ can be determined with almost no non-perturbative uncertainties. Finally we explain how this precise determination of the standard model values can be used to find possible new physics contributions in $\Delta M_s$, $\Delta {\Gamma }_s$, $\Delta {\Gamma }_s/\Delta M_s$ and $a_{fs}^s$. Combining the latest experimental bounds on these quantities one already gets some hints for new physics contributions.

Comments: 16 pages, 3 figures, plenary talk at Heavy Quarks and Leptons 16.10. - 20.10.2006 Munich, Germany; to appear in the proceedings