Analysis of neutral-D decays to a charged kaon, a charged pion, and a neutral pion: Search for neutral-D mixing, and measurements of the doubly Cabibbo-suppressed decay rate and resonance contributions

Analyzing D0 → K +pi-pi0 decays, herein are presented the methods and results of a search for D0- D¯0 mixing, a measurement of the branching ratio R ≡ Gamma(D0 → K+pi-pi0)/Gamma( D0 → K-pi +pi0), and measurements of the contributions from D0 → K+pi -, K*+pi-, K*0pi0; 230.4fb-1 of data collected from the BABAR detector at the PEP-II collider during 2000-2004 (Runs 1-4) are analyzed. An event-level tagging technique is developed, which facilitates the accurate determination of doubly Cabibbo-suppressed resonance contributions by suppressing background from Cabibbo-favored decays. The branching ratio is measured as R = (0.214 +/- 0.008 (stat)+/-0.008 (syst))%, with (46.1+/-3.3 (stat)+/-2.9 (syst))% of D0 → K+pi -pi0 decays proceeding through the channel D0 → K*+pi -. The data are consistent with the null-D-mixing hypothesis at a confidence level of 10%, and the expected value of +/- x2+y2 is measured as -0.013 +/- 0.010 (stat), indicating negative interference between mixing and doubly Cabibbo-suppressed decay. The expected value of the integrated mixing rate is (x2 + y2)/2 = (0.013 +/- 0.013 (stat))%.