Use of early data on B -> rho pi decays - art. no. 054002

This paper reviews the Dalitz plot analysis for the decays B-0((B) over bar (0))-->rho pi-->pi(+)pi(-)pi(0). We discuss what can be learned about the t en parameters in this analysis from untagged and from tagged time-integrate d data. We find that, with the important exception of the interesting CP vi olating quantity alpha, the parameters can be determined from this data sam ple-and, hence, they can be measured at CLEO as well as at the asymmetric B factories. This observation also suggests that the extraction of alpha fro m the time-dependent data sample can he accomplished with a smaller data sa mple (and, therefore, sooner) than would be required if all ten parameters were to be obtained from the well-tagged time-dependent data sample alone. We also explore bounds on the shift of the true angle alpha from the angle measured from charged rho final states alone. These may be obtained prior t o measurements of the parameters describing the neutral rho channel, which are expected to be small.