Time-Dependent $CP$-Violating Asymmetry in ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\rho}}^{0}\ensuremath{\gamma}$ Decays

Time-Dependent $C P$ -Violating Asymmetry in $B^{0} \to ρ^{0} γ$ Decays

Y. Ushiroda et al. (Belle Collaboration)

Phys. Rev. Lett. 100, 021602 – Published 18 January 2008

Abstract

We report the first measurement of $C P$ -violation parameters in $B^{0} \to ρ^{0} γ$ decays based on a data sample of $657 \times 10^{6} B \bar{B}$ pairs collected with the Belle detector at the KEKB asymmetric-energy $e^{+} e^{-}$ collider. We obtain the time-dependent and direct $C P$ -violating parameters, $S_{ρ^{0} γ} = - 0.83 \pm 0.65 (stat) \pm 0.18 (syst)$ and $A_{ρ^{0} γ} = - 0.44 \pm 0.49 (stat) \pm 0.14 (syst)$ , respectively.