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  • Measurements of isospin asy...
    Watanuki, S

    Physical review. D, 02/2019, Letnik: 99, Številka: 3
    Journal Article

    We report measurements of isospin asymmetry Δ0− and difference of direct CP asymmetries ΔACP between charged and neutral B→Xsγ decays. This analysis is based on the data sample containing 772×106BB¯ pairs that was collected with the Belle detector at the KEKB energy-asymmetric e+e− collider. Using a sum-of-exclusive technique with invariant Xs mass up to 2.8 GeV/c2, we obtain Δ0−=−0.48±1.49(stat)±0.97(syst)±1.15(f+−/f00)% and ΔACP=+3.69±2.65(stat)±0.76(syst)%, where the last uncertainty for Δ0− is due to the uncertainty on the production ratio of B+B− to B0B¯0 in (4S) decays. The measured value of Δ0− is consistent with zero, allowing us to constrain the resolved photon contribution in the B→Xsγ, and improve the branching fraction prediction. The result for ΔACP is consistent with the prediction of the SM. We also measure the direct CP asymmetries for charged and neutral B→Xsγ decays. All the measurements are the most precise to date.