First observation of B¯-->D(*)ρ'-, ρ'--->ωπ-

We report on the observation of B¯-->D^*π⁺π^-π^-π⁰ decays. The branching ratios for D^*+ and D^*0 are (1.72+/-0.14+/-0.24)% and (1.80+/-0.24+/-0.27)%, respectively. Each final state has a D^*ωπ^- component, with branching ratios (0.29+/-0.03+/-0.04)% and (0.45+/-0.10+/-0.07)% for the D^*+ and D^*0 modes, respectively. We also observe B¯-->Dωπ^- decays. The branching ratios for D⁺ and D⁰ are (0.28+/-0.05+/-0.04)% and (0.41+/-0.07+/-0.06)%, respectively. A spin parity analysis of the ωπ^- system in the Dωπ^- final state shows a preference for a wide 1^- resonance. A fit to the ωπ^- mass spectrum finds a central mass of (1349+/-25⁺¹⁰_-5) MeV and width of (547+/-86⁺⁴⁶_-45) MeV. We identify this object as the ρ(1450) or the ρ'.