Observation of CP Violation in B[superscript 0]→K[superscript +]π[superscript -] and B[superscript 0]→π[superscript +]π[superscript -]

Abstract

We report observations of CP violation in the decays B[superscript 0]→K[superscript +]π[superscript -] and B[superscript 0]→π[superscript +]π[superscript -] in a sample of 383×10[superscript 6] Υ(4S)→BB̅ events. We find 4372±82 B[superscript 0]→K[superscript +]π[superscript -] decays and measure the direct CP-violating charge asymmetry A[subscript Kπ]=-0.107±0.018(stat)[subscript -0.004][[superscript +0.007](syst), which excludes the CP-conserving hypothesis with a significance of 5.5 standard deviations. In the same sample, we find 1139±49 B[superscript 0]→π[superscript +]π[superscript -] decays and measure the CP-violating asymmetries S[subscript ππ]=-0.60±0.11(stat)±0.03(syst) and C[subscript ππ]=-0.21±0.09(stat)±0.02(syst). CP conservation in B[superscript 0]→π[superscript +]π[superscript -] (S[subscript ππ]=C[subscript ππ]=0) is excluded at a confidence level 1-C.L.=8×10[superscript -8], corresponding to 5.4 standard deviations.