Study of B0 → D(*)0π+π- decays

We report on a study of B 0 → D(*)0 π+π- decays using 29.1 fb-1 of e+e- annihilation data recorded at the γ(4S) resonance with the Belle detector at the KEKB storage ring. Making no assumptions about the intermediate mechanism, the branching fractions for B 0 → D0π+π- and B 0 → D*+π+π- are determined to be (8.0 ± 0.6 ± 1.5) x 10-4 and (6.2 ± 1.2 ± 1.8) × 10-4, respectively. An analysis of B 0 → D0π+π- candidates yields to the first observation of the color-suppressed hadronic decay B 0 → D0ρ0 with the branching fraction (2.9 ± 1.0 ± 0.4) × 10-4. We measure the ratio of branching fractions Β(B 0 → D0ρ0)/Β(B 0 → D0ω) = 1.6 ± 0.8. © 2002 Elsevier Science B.V. All rights reserved.