Final State Rescattering and Color-suppressed \bar B^0-> D^{(*)0} h^0 Decays

Abstract

The color-suppressed \bar B^0-> D^{(*)0}π^0, D^{(*)0}η, D^0ωdecay modes have just been observed for the first time. The rates are all larger than expected, hinting at the presence of final state interactions. Considering \bar B^0-> D^{(*)0}π^0 mode alone, an elastic D^{(*)}π-> D^{(*)}πrescattering phase difference δ\equiv δ_{1/2} - δ_{3/2} \sim 30^\circ would suffice, but the \bar B^0-> D^{(*)0}η, D^0ωmodes compel one to extend the elastic formalism to SU(3) symmetry. We find that a universal a_2/a_1=0.25 and two strong phase differences 20^\circ \sim θ< δ< δ^\prime \sim 50^\circ can describe both DP and D^*P modes rather well; the large phase of order 50^\circ is needed to account for the strength of {\it both} the D^{(*)0}π^0 and D^{(*)0}ηmodes. For DV modes, the nonet symmetry reduces the number of physical phases to just one, giving better predictive power. Two solutions are found. We predict the rates of the \bar B^0-> D^{+}_s K^-, D^{*+}_s K^-, D^0ρ^0, D^+_s K^{*-} and D^0ϕmodes, as well as \bar B^0-> D^{0}\bar K^0, D^{*0}\bar K^0, D^{0}\bar K^{*0} modes. The formalism may have implications for rates and CP asymmetries of charmless modes.