A New Gold Standard of the Weak Phase β Obtained by Combined BABAR + Belle CP Violation Measurements of B^0→D^(∗)_(CP)h^0 Decays

The B factory experiments, BABAR at SLAC in the USA and Belle at KEK in Japan, established CP violation in the B meson system and contributed to a better understanding of the quark-flavor structure of the Standard Model. In this contribution to the FPCP 2016 proceedings the results of a new analysis campaign are summarized, which combines for the first time the large final data sets of both experiments in a single physics analysis. The measurement of the time-dependent CP violation in B^0→D^(∗)_(CP)h^0 decays and a first observation of CP violation governed by the weak phase b is reported. B^0→D^(∗)_(CP)h^0 decays will provide a very clean Standard Model reference for the new physics searches in penguin-dominated b→s transitions at the future high-luminosity B factory experiment Belle II