Extracting the unitarity angle γ in Bs→D0h0,D¯0h0 decays

The recently observed color-suppressed B¯0→D0π0, D0η(′), Ds+K−, D0K¯0, D0ρ0 and D0ω decay modes all have rates larger than expected. The color-suppressed Bs→D0ϕ, D¯0ϕ modes, which were suggested for the extraction of the unitarity angle γ in the Gronau-London method, could be larger than the previous estimation in rates by one order of magnitude. Several new theoretical clean modes in Bs decays are suggested for the extraction of γ. The proposed Bs→D0h0, D¯0h0 decay modes with h0=π0,η,η′,ρ0,ω in addition to h0=ϕ are free from penguin contributions. Their decay rates can be estimated from the observed color-suppressed B¯0→D0h0 rates through SU(3) symmetry. A combined study of these D0h0, D¯0h0 modes in addition to the D0ϕ, D¯0ϕ modes is useful in the extraction of γ in the Bs system without involving Bs-B¯s mixing. Since the b→u and b→c transitions belong to the same topological diagram, the relative strong phase is likely to be small. In this case, the CP asymmetries are suppressed and the untagged rates are very useful in the γ extraction.