Measurement of the $CP$ violation parameter $A_{\hat{I}}“$ in $D^0\to K^{+}{K}^{-}$ and $D^0\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}$ decays

Abstract

Asymmetries in the time-dependent rates of $D^0\to K^{+}{K}^{-}$ and $D^0\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}$ decays are measured in a $pp$ collision data sample collected with the LHCb detector during LHC Run 1, corresponding to an integrated luminosity of $3{\mathrm{fb}}^{-1}$. The asymmetries in effective decay widths between $D^0$ and ${\overline{D}}^0$ decays, sensitive to indirect $CP$ violation, are measured to be $A_{\hat{I}}“(K^{+}{K}^{-})=(-0.30\pm 0.32\pm 0.10)\times 10^{-3}$ and $A_{\hat{I}}“(\ddot{I}{€}^{+}\ddot{I}{€}^{-})=(0.46\pm 0.58\pm 0.12)\times 10^{-3}$, where the first uncertainty is statistical and the second systematic. These measurements show no evidence for $CP$ violation and improve on the precision of the previous best measurements by nearly a factor of two.

All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-063.html