CP-violating effects in the time-dependent angular distribution of thedecay products play a key rôle for the search of new physics. The hadronic Standard-Model uncertainties are related to doubly Cabibbo-suppressed penguin contributions and are usually assumed to be negligibly small. In view of recent results from the Tevatron and the quickly approaching start of the data taking at the LHC, we have a critical look at the impact of these terms, which could be enhanced through long-distance QCD phenomena, and explore the associated uncertainty for the measurement of the CPviolating B 0 s -B 0 s mixing phase. We point out that these effects can actually be controlled by means of an analysis of the time-dependent angular distribution of the B 0decay products, and illustrate this through numerical studies. Moreover, we discuss SU (3)-breaking effects, which limit the theoretical accuracy of our method, and suggest internal consistency checks of SU (3).

CP violation is a major challenge of contemporary particle physics. It has been discovered in kaon decays and appears also in B decays, where the B 0 ! J=c K S;L channels are considered to be clean probes of this phenomenon. Recent B-factory data challenge the description of CP violation in the standard model of particle physics, showing some ''tension'' with theoretical predictions. We take a detailed look at certain standard-model contributions, which are usually neglected, and point out that they can be included unambiguously through measurements of the B 0 ! J=c 0 observables. Using the most recent data, we show that the tension with the standard model is softened, and we constrain a possible new-physics phase in B 0 À " B 0 mixing. Our strategy is crucial to fully exploit the accuracy of the search for this kind of new physics at the LHC and future super-flavor factories.