Observation of CP violation in two-body B0 (s)-meson decays to charged pions and kaons

The time-dependent CP asymmetries of B0 → π+π− and B0s → K+K− decays
are measured using a data sample of pp collisions corresponding to an integrated luminosity of 1.9 fb−1, collected with the LHCb detector at a centre-of-mass energy of 13 TeV. The results are
Cππ = −0.311 ± 0.045 ± 0.015,
Sππ = −0.706 ± 0.042 ± 0.013,
CKK = 0.164 ± 0.034 ± 0.014,
SKK = 0.123 ± 0.034 ± 0.015,
A∆Γ
KK = −0.83 ± 0.05 ± 0.09,
where the first uncertainties are statistical and the second systematic. The same data sample is used to measure the time-integrated CP asymmetries of B0 → K + π− and B0s → K−π+ decays and the results are
AB0CP = −0.0824 ± 0.0033 ± 0.0033,
AB0s CP = 0.236 ± 0.013 ± 0.011.
All results are consistent with earlier measurements. A combination of LHCb measurements provides the first observation of time-dependent CP violation in B0s decays.