Numerical updates of lifetimes and mixing parameters of B mesons.

Abstract

We update the Standard-Model predictions for several quantities related to Bs−B¯s and Bd−B¯d mixing. The mass and width differences in the Bs system read ΔMSMs=(17.3±2.6)ps−1 and ΔΓSMs=(0.087±0.021)ps−1, respectively. The CP asymmetries in flavour-specific decays are as,SMfs=(1.9±0.3)⋅10−5 and ad,SMfs=−(4.1±0.6)⋅10−4. We further critically discuss the sensitivity of ΔΓd to new physics and the uncertainties in the relation between ΔΓs and the branching fraction of Bs→D(∗)s+D(∗)s−. Then we present a numerical update of the average width Γs in the Bs system and correlate Γs with the B+-Bd lifetime ratio. Finally we summarise the key results of our recent global analysis with the CKMfitter collaboration addressing new physics in B−B¯-mixing. In an appropriately defined scenario parametrising new physics in B−B¯-mixing by two complex parameters Δd and Δs the Standard-Model point {Δd=Δs=1} is disfavoured by 3.6 standard deviations.