Complete analysis of all B -> pi K decays

The Standard Model (SM) predicts that Delta A(CP), the difference between the direct CP asymmetries for the modes B+ -> pi K-0(+) and B-0 -> pi K--(+) that are related by a weak isospin, should be close to zero. There has been a recent claim by the LHCb Collaboration that the measured value of Delta A(CP) shows an uncomfortable tension with the SM prediction, almost at the 8 sigma level. Motivated by this claim, we critically reexamine the data on all the B -> pi K modes, including the CP asymmetries and CP-averaged branching fractions. From a combined Bayesian analysis with the topological amplitudes and their phases as the free parameters, we find that the best-fit region has a large overlap with the parameter space favored in the SM, albeit with some enhancement for the electroweak penguin and the color-suppressed tree amplitudes; consistent with the findings of earlier studies. We find that in this SM-like region, Delta A(CP) is more than 5 sigma away from zero and the tension with the global average, as well as the LHCb result, is within 2 sigma. Thus, we conclude that there is not yet enough motivation to go beyond the SM.