Observation of ${D}^{0}\text{\ensuremath{-}}{\overline{D}}^{0}$ Mixing in ${e}^{+}{e}^{\ensuremath{-}}$ Collisions

Observation of $D^{0} − {\bar{D}}^{0}$ Mixing in $e^{+} e^{-}$ Collisions

B. R. Ko et al. (Belle Collaboration)

Phys. Rev. Lett. 112, 111801 – Published 17 March 2014; Erratum Phys. Rev. Lett. 112, 139903 (2014)

Abstract

We observe $D^{0} − {\bar{D}}^{0}$ mixing in the decay $D^{0} \to K^{+} π^{-}$ using a data sample of integrated luminosity $976 {fb}^{- 1}$ collected with the Belle detector at the KEKB $e^{+} e^{-}$ asymmetric-energy collider. We measure the mixing parameters ${x^{'}}^{2} = (0.09 \pm 0.22) \times 1 0^{- 3}$ and $y^{'} = (4.6 \pm 3.4) \times 1 0^{- 3}$ and the ratio of doubly Cabibbo-suppressed to Cabibbo-favored decay rates $R_{D} = (3.53 \pm 0.13) \times 1 0^{- 3}$ , where the uncertainties are statistical and systematic combined. Our measurement excludes the no-mixing hypothesis at the 5.1 standard deviation level.