$\mathit CP$ 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