Angular analysis of ${B}^{0}\ensuremath{\rightarrow}\ensuremath{\phi}{K}^{*}$ decays and search for $CP$ violation at Belle

Angular analysis of $B^{0} \to ϕ K^{*}$ decays and search for $C P$ violation at Belle

M. Prim et al. (Belle Collaboration)

Phys. Rev. D 88, 072004 – Published 10 October 2013

Abstract

We report the measurements of branching fractions and $C P$ violation asymmetries in $B^{0} \to ϕ K^{*}$ decays obtained in an angular analysis using the full data sample of $772 \times 10^{6} B \bar{B}$ pairs collected at the $Υ (4 S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+} e^{-}$ collider. We perform a partial wave analysis to distinguish among scalar [ $B^{0} \to ϕ (K π)_{0}^{*}$ ], vector [ $B^{0} \to ϕ K^{*} (892)^{0}$ ] and tensor [ $B^{0} \to ϕ K_{2}^{*} (1430)^{0}$ ] components, and determine the corresponding branching fractions to be $B [B^{0} \to ϕ (K π)_{0}^{*}] = (4.3 \pm 0.4 \pm 0.4) \times 10^{- 6}$ , $B [B^{0} \to ϕ K^{*} (892)^{0}] = (10.4 \pm 0.5 \pm 0.6) \times 10^{- 6}$ and $B [B^{0} \to ϕ K_{2}^{*} (1430)^{0}] = ({5.5}_{- 0.7}^{+ 0.9} \pm 1.0) \times 10^{- 6}$ . We also measure the longitudinal polarization fraction $f_{L}$ in $B^{0} \to ϕ K^{*} (892)^{0}$ and $B^{0} \to ϕ K_{2}^{*} (1430)^{0}$ decays to be $0.499 \pm 0.030 \pm 0.018$ and ${0.918}_{- 0.060}^{+ 0.029} \pm 0.012$ , respectively. The first quoted uncertainties are statistical and the second are systematic. In total, we measure 26 parameters related to branching fractions, polarization and $C P$ violation in the $B^{0} \to ϕ K^{*}$ system. No evidence for $C P$ violation is found.