Amplitude analysis of B0→K+π-π0 [B superscript 0 →K superscript + pi superscript - pi superscript 0] and evidence of direct CP violation in B→K*π [B → K superscript asterisk pi] decays

Abstract

We analyze the decay B0→K+π-π0 [B superscript 0 →K superscript + pi superscript - pi superscript 0] with a sample of 4.54×108 [4.54 x 10 superscript 8] BB̅ [B B overstrike] events collected by the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC, and extract the complex amplitudes of seven interfering resonances over the Dalitz plot. These results are combined with amplitudes measured in B0→KS0π+π- [B superscript 0 →K subscript S superscript 0 pi superscript + pi superscript -] decays to construct isospin amplitudes from B0→K*π [B superscript 0 → K superscript * pi] and B0→ρK [B superscript 0 → pK] decays. We measure the phase of the isospin amplitude Φ3/2 [phi subscript 3/2], useful in constraining the Cabibbo-Kobayashi-Maskawa unitarity triangle angle γ and evaluate a CP rate asymmetry sum rule sensitive to the presence of new physics operators. We measure direct CP violation in B0→K*+π- [B superscript 0 → K superscript * + pi superscript -] decays at the level of 3σ [3 delta] when measurements from both B0→K+π-π0 [B superscript 0 →K superscript + pi superscript - pi superscript 0] and B0→KS0π+π- [B superscript 0 →K subscript S superscript 0 pi superscript + pi superscript -]decays are combined.