Measuring 2beta+gamma with color-allowed B0 -> D+- Ks pi-+ decays

We present a method to measure the weak phase 2beta+gamma in the three-body decay B0 -> D± Ks pi-+. These decays are mediated by interfering amplitudes which are color-allowed and hence relatively large. In addition, the three-body decay helps to resolve discrete ambiguities present in measurements of the weak phase. The experimental implications are discussed, and the sensitivity of the method is evaluated using a simulation.