CP violation in the B0 meson system with BaBar

Abstract The BABAR detector, at the PEP-II asymmetric B Factory at SLAC collected a sample of 32 million B B pairs whilst operating at energies near the γ(4S) resonance between October 1999 and May 2001. A study of time-dependent CP-violating asymmetries in events where one neutral B meson is fully reconstructed in a final state containing charmonium produced the measurement sin 2β = 0.59 ± 0.14 (stat) ± 0.05 (syst), which constitutes an observation of CP violation in the B0 meson system at the 4σ level. Also presented are preliminary results from a study of CP violation in the decays b0 → π+π− and B0 → K+π−.