Observation of D0-D̄0 oscillations

Abstract

We report a measurement of the time-dependent ratio of D0→K +π- to D0→K-π+ decay rates in D*+-tagged events using 1.0 fb-1 of integrated luminosity recorded by the LHCb experiment. We measure the mixing parameters x′2=(-0.9±1.3)×10-4, y′=(7.2±2.4)×10-3, and the ratio of doubly-Cabibbo-suppressed to Cabibbo-favored decay rates RD=(3. 52±0.15)×10-3, where the uncertainties include statistical and systematic sources. The result excludes the no-mixing hypothesis with a probability corresponding to 9.1 standard deviations and represents the first observation of D0-D̄0 oscillations from a single measurement. © 2013 CERN.