Study of CP asymmetries in charmless hadronic B decays: Toward a measurement of α

We present preliminary measurements of time-dependent CP asymmetries in neutral B meson decays to π⁺ π^- and π⁺ π^- π⁰ final states, where the latter is measured in the region of the Dalitz plane dominated by the ρ resonance. We also present preliminary measurements of the branching fraction for the decay B ⁺ → π⁺ π⁰ and an improved upper limit for B⁰ → π⁰ π⁰, both of which are needed to extract the CP parameter α from the time-dependent CP asymmetry in the π⁺ π^- channel. These results are obtained from a data sample of approximately 88 million Υ(4S) → BB̄ decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC.