Measuring the CP angle β in hadronic b → s penguin decays

Asymmetric e+e− colliders running on the ϒ(4S) (B factories) will much more readily measure CP-violating asymmetries in the decays of Bd0 and B± mesons than in the decays of Bs0 mesons. As such, they will seemingly not be able to probe new phases in Bs0-Bs0 mixing, i.e. in b → s transitions. However, by measuring the CP angle β via b → s hadronic penguin decays such as Bd→ η′Ks and Bd→φ Ks, and comparing its value to that obtained in Bd→Ψ Ks, it is possible to detect the presence of new physics in the b → s flavor-changing neutral current. Recent CLEO results are encouraging in this regard. They suggest that the branching ratio of the b → s penguin decay Bd0 → η′Ks is anomalously large, about 4 × 10−5, which will make it much easier to search for new physics in b → s transitions.