Measurement of Branching Fractions and Resonance Contributions for B0 -> D0bar K+ pi- and Search for B0 -> D0 K+ pi- Decays

Abstract

Using 226 million ${\rm Y}(4S)\to B\bar{B}$ events collected with the BaBar detector at the PEP-II $e^{+}{e}^{-}$ storage ring at the Stanford Linear Accelerator Center, we measure the branching fraction for $B^0\to {\bar{D}}^0{K}^{+}{\pi }^{-}$, excluding $B^0\to D^{\ast -}{K}^{+}$ to be $\mathcal{B}(B^0\to {\bar{D}}^0{K}^{+}{\pi }^{-})=(88\pm 15\pm 9)\times 10^{-6}.$ We observe $B^0\to {\bar{D}}^0{K}^{\ast }(892{)}^0$ and $B^0\to D_2^{\ast }(2460{)}^{-}{K}^{+}$ contributions. The ratio of branching fractions $\mathcal{B}(B^0\to D^{\ast -}{K}^{+})/\mathcal{B}(B^0\to D^{\ast -}{\pi }^{+})=(7.76\pm 0.34\pm 0.29)$ is measured separately. The branching fraction for the suppressed mode $B^0\to D^0{K}^{+}{\pi }^{-}$ is $\mathcal{B}(B^0\to D^0{K}^{+}{\pi }^{-})<19\times 10^{-6}$ at the 90% confidence level.

7 pages, 3 figures, published on Phys.Rev.Lett. 96, 011803 (2006)