Implications of the Dimuon CP Asymmetry in Bd,s Decays

The D0 Collaboration reported a 3.2 sigma deviation from the standard model (SM) prediction in the likesign dimuon asymmetry. Assuming that new physics contributes only to B-d,B-s mixing, we show that the data can be analyzed without using the theoretical calculation of Delta Gamma(s), allowing for robust interpretations. We find that this framework gives a good fit to all measurements, including the recent CDF Collaboration S-psi phi result. The data allow universal new physics with similar contributions relative to the SM in the B-d and B-s systems, but favors a larger deviation in B-s than in B-d mixing. The general minimal flavor violation framework with flavor diagonal CP violating phases can account for the former case and remarkably even for the latter case. This observation makes it simpler to speculate about which extensions with general flavor structure may also fit the data.