Measurements of Branching Fraction and Polarization in B^+ -> rho^+ K^{*0} Decay

Abstract

We present the results of a study of the charmless vector-vector decay $B^+\to ρ^+K^{*0}$, based on 253 fb$^{-1}$ of data collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We obtain the branching fraction ${\cal B}(B^+\toρ^+ K^{*0})=(8.9\pm 1.7(\rm stat)\pm 1.2 (\rm syst))\times 10^{-6}$. We also perform a helicity analysis of the $ρ$ and $K^*$ vector mesons, and obtain the longitudinal polarization fraction $f_L(B^+\to ρ^+ K^{*0})=0.43 \pm 0.11(\rm stat)^{+0.05}_{-0.02}(\rm syst)$.