Evidence for direct CP violation from Dalitz-plot analysis of B±→K±π∓π±

Abstract

We report a Dalitz-plot analysis of the charmless hadronic decays of charged B mesons to the final state K ± π ∓ π ± . Using a sample of ( 383.2 ± 4.2 ) × 10 6 B ¯¯¯ B pairs collected by the BABAR detector, we measure C P -averaged branching fractions and direct C P asymmetries for intermediate resonant and nonresonant contributions. We find evidence for direct C P violation in the decay B ± → ρ 0 ( 770 ) K ± , with a C P -violation parameter A C P = ( + 44 ± 10 ± 4 + 5 − 13 ) % .