Evidence for CP violation in B^+ → K∗(892)^+π^0 from a Dalitz plot analysis of B^+ → K^0_Sπ^+π^0 decays

Abstract

We report a Dalitz plot analysis of charmless hadronic decays of charged B mesons to the final state K^0_Sπ^+π^0 using the full BABAR data set of 470.9±2.8  million BB[overbar] events collected at the Υ(4S)resonance. We measure the overall branching fraction and CP asymmetry to be B(B^+→K^0π^+π^0)=(31.8±1.8±2.1+^(6.0)_(−0.0))×10^(-6) and A_(CP)(B^+→K^0π^+π^0)=0.07±0.05±0.03^(+0.02)_(−0.03), where the uncertainties are statistical, systematic, and due to the signal model, respectively. This is the first measurement of the branching fraction for B^+→K^0π^+π^0. We find first evidence of a CP asymmetry in B^+→K∗(892)+π^0 decays: A_(CP)(B^+→K∗(892)^+π^0)=−0.52±0.14±0.04^(+0.04)_(−0.02). The significance of this asymmetry, including systematic and model uncertainties, is 3.4 standard deviations. We also measure the branching fractions and CP asymmetries for three other intermediate decay modes.

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