Search for D0−¯¯¯D0 Mixing and Branching-Ratio Measurement in the Decay D0→K+π−π0

Abstract

We analyze 230.4 fb − 1 of data collected with the BABAR detector at the PEP-II e + e − collider at SLAC to search for evidence of D 0 − ¯¯¯ D 0 mixing using regions of phase space in the decay D 0 → K + π − π 0 . We measure the time-integrated mixing rate R M = ( 0.023 + 0.018 − 0.014 ( stat . ) ± 0.004 ( syst . ) ) % , and R M < 0.054 % at the 95% confidence level, assuming C P invariance. The data are consistent with no mixing at the 4.5% confidence level. We also measure the branching ratio for D 0 → K + π − π 0 relative to D 0 → K − π + π 0 to be ( 0.214 ± 0.008 ( stat . ) ± 0.008 ( syst . ) ) % .