Measurement of CP asymmetries and branching fractions in a time-dependent Dalitz analysis of B-0 ->(rho pi)(0) and a constraint on the quark mixing angle phi(2)

Abstract

We present the results of a time-dependent Dalitz plot analysis of B-0 ->pi(+)pi(-)pi(0) decays based on a 414 fb(-1) data sample that contains 449x10(6)B (B) over bar pairs. The data were collected on the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric energy e(+)e(-) collider. Combining our analysis with information on charged B decay modes, we perform a full Dalitz and isospin analysis and obtain a constraint on the quark mixing angle phi(2), 68 degrees <phi(2)< 95 degrees at the 68.3% confidence level for the phi(2) solution consistent with the standard model. A large standard-model-disfavored region also remains. The branching fractions for the decay processes B-0 ->rho(+/-)(770)pi(-/+) and B-0 ->rho(0)(770)pi(0) are measured to be (22.6 +/- 1.1[stat]+/- 4.4[syst])x10(-6) and (3.0 +/- 0.5[stat]+/- 0.7[syst])x10(-6), respectively. These are the first branching fraction measurements of the process B-0 ->rho(770)pi with the lowest resonance rho(770) explicitly separated from the radial excitations.