Measurement of time-integrated $D^0\to hh$ asymmetries at LHCb

LHCb collected the world’s largest sample of charm decays during LHC Run I, corresponding to an integrated luminosity of 3fb$^{−1}$. This has permitted many precision measurements of charm mixing and CP violation parameters. One of the most precise and important observables is the so-called $\Delta A_{CP}$ parameter, corresponding to the difference between the time-integrated CP asymmetry in singly Cabibbo-suppressed $D^{0} \rightarrow K^{+}K^{-}$ and $D^{0} \rightarrow \pi^{+}\pi{-}$ decay modes. The flavour of the $D^{0}$ meson is inferred from the charge of the pion in $D^{∗+} \rightarrow D^{0}\pi^{+}$ and $D^{∗−} \rightarrow \overline{D}^{0}\pi^{-}$ decays. $\Delta A_{CP} \equiv A_{raw}(K^{+}K^{−})−A_{raw}(\pi^{+}\pi{−})$ is measured to be $\Delta A_{CP}=(−0.10±0.08±0.03)$%, where the first uncertainty is statistical and the second systematic. The measurement is consistent with the no- CP -violation hypothesis and represents the most precise measurement of time-integrated CP asymmetry in the charm sector.