Measurement of D0-D0bar Mixing Using the Ratio of D0-]K-pi and K-K Lifetimes

Download or read book Measurement of D0-D0bar Mixing Using the Ratio of D0-]K-pi and K-K Lifetimes written by and published by . This book was released on 2009 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: We measure the rate of D°-{bar D}° mixing with the observable y{sub CP} = (?{sub K?}/?{sub KK}) - 1, where?{sub KK} and?{sub K?} are respectively the mean lifetimes of CP-even D° → KK− and CP-mixed D° → K−?+ decays, using a data sample of 384 fb−1 collected by the BABAR detector at the SLAC PEP-II asymmetric-energy B Factory. From a sample of D° and {bar D}° decays where the initial flavor of the decaying meson is not determined, we obtain y{sub CP} = [1.12 ± 0.26(stat) ± 0.22(syst)]%, which excludes the no-mixing hypothesis at 3.3?, including both statistical and systematic uncertainties. This result is in good agreement with a previous BABAR measurement of y{sub CP} obtained from a sample of D*+ → D°?+ events, where the D° decays to K−?+, K+K−, and {pi}+{pi}−, which is disjoint with the untagged D° events used here. Combining the two results taking into account statistical and systematic uncertainties, where the systematic uncertainties are assumed to be 100% correlated, we find y{sub CP} = [1.16 ± 0.22(stat) ± 0.18(syst)]%, which excludes the no-mixing hypothesis at 4.1?