Direct CP Violation in $B^\pm\toρ^\pmπ^+π^-$ in the $ρ^0$-$ω$ Interference Region

Abstract

We study direct CP violation in $B^\pm \to ρ^\pmρ^0(ω) \to ρ^\pmπ^+π^-$ and focus specifically on the rate asymmetry in the $ρ^0$-$ω$ interference region. Here the strong phase is dominated by isospin violation, so that it can be essentially determined by $e^+e^- \to ρ^0 (ω) \to π^+π^-$ data. We find the CP-violating asymmetry to be of the order of 20% at the $ω$ invariant mass. Moreover, it is robust with respect to the estimable strong-phase uncertainties, permitting the extraction of $\sinα$ from this channel.