CHARMLESS 2- AND 3-BODY B DECAYS AND THE ANGLE α (φ_2)

摘要

We present preliminary measurements of branching fractions and CP-asymmetry parameters in two-and three-body charmless hadronic B decays. The available data sample consists of 227 million Υ(4S) → BB decays collected with the BABAR detector at the PEP-II asymmetric-energy e~+e~-collider at SLAC. We establish the observation of the decays B~0 → π~0 π~0 and B~0 → K~0K~0 and constrain the CKM angle α with a full SU(2) isospin analysis in the B → ππ system and with a B~0 → π~+ π~- π~0 time - dependent Dalitz plot analysis.