$\mathit CP$ violation in these modes can come from the decay amplitudes (direct) and/or from mixing or interference of mixing and decay (indirect). The difference $\Delta \mathit A_{CP}$ is primarily sensitive to the direct component, and only retains a second-order dependence on the indirect component for measurements where the mean decay time of the ${{\mathit K}^{+}}{{\mathit K}^{-}}$ and ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ samples are not identical. The results below are averaged assuming the indirect component can be neglected.

VALUE (%) EVTS DOCUMENT ID TECN  COMMENT $-0.154$ $\pm0.029$ 53M,17M AAIJ 2019 D LHCB Time-integrated • • We do not use the following data for averages, fits, limits, etc. • • $-0.10$ $\pm0.08$ $\pm0.03$ 6.5M,2.2M AAIJ 2016 D LHCB See AAIJ 2019D $0.14$ $\pm0.16$ $\pm0.08$ 2.2M,0.8M AAIJ 2014 AK LHCB See AAIJ 2019D $0.49$ $\pm0.30$ $\pm0.14$ 0.56M,0.22M AAIJ 2013 AD LHCB See AAIJ 2014AK $-0.82$ $\pm0.21$ $\pm0.11$ 1.4M,0.4M AAIJ 2012 G LHCB See AAIJ 2016D $-0.46$ $\pm0.31$ $\pm0.12$ AALTONEN 2012 B CDF See AALTONEN 2012O $-0.62$ $\pm0.21$ $\pm0.10$ AALTONEN 2012 O CDF Time-integrated $0.24$ $\pm0.62$ $\pm0.26$ 1 AUBERT 2008 M BABR Time-integrated $-0.86$ $\pm0.60$ $\pm0.07$ 120k STARIC 2008 BELL Time-integrated 1  Calculated from the AUBERT 2008M values of $\mathit A_{CP}$( ${{\mathit K}^{+}}{{\mathit K}^{-}}$ ) and $\mathit A_{CP}$( ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ ). The systematic error here combines the systematic errors in quadrature, and therefore somewhat over-estimates it.

Conservation Laws:

$\mathit CP$ VIOLATION OBSERVED

References:

AAIJ 2019D PRL 122 211803 Observation of CP Violation in Charm Decays AAIJ 2016D PRL 116 191601 Measurement of the Difference of Time-Integrated $\mathit CP$ Asymmetries in ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit K}^{-}}{{\mathit K}^{+}}$ and ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit \pi}^{-}}{{\mathit \pi}^{+}}$ Decays AAIJ 2014AK JHEP 1407 041 Measurement of $\mathit CP$ Asymmetry in ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit K}^{-}}{{\mathit K}^{+}}$ and ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit \pi}^{-}}{{\mathit \pi}^{+}}$ Decays AAIJ 2013AD PL B723 33 Search for Direct $\mathit CP$ Violation in ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit h}^{-}}{{\mathit h}^{+}}$ Modes using Semileptonic ${{\mathit B}}$ Decays AAIJ 2012G PRL 108 111602 Evidence for $\mathit CP$ Violation in Time-Integrated ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit h}^{-}}{{\mathit h}^{+}}$ Decay Rates AALTONEN 2012B PR D85 012009 Measurement of $\mathit CP$-Violating Asymmetries in ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ and ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}$ Decays at CDF AALTONEN 2012O PRL 109 111801 Measurement of the Difference in $\mathit CP$-Violating Asymmetries in ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}$ and ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ Decays at CDF AUBERT 2008M PRL 100 061803 Search for $\mathit CP$ Violation in the Decays D0-->K-K+ and ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit \pi}^{-}}{{\mathit \pi}^{+}}$ STARIC 2008 PL B670 190 Search for a $\mathit CP$ Asymmetry in Cabibbo-Suppressed ${{\mathit D}^{0}}$ Decays