CP violation and lifetime measurements in the decay B${}_s^0\to$ J/$\psi$ K${}^{-}$K${}^{+}$ with the LHCb experiment

Within the Standard Model (SM) the CP violating phase ${\varphi }_s$ of the decay B${}_s^0\to$ J/$\psi$ K${}^{-}$K${}^{+}$ can be precisely constrained from indirect measurements. This makes the direct measurement of ${\varphi }_s$ a sensitive test of the SM. A flavor tagged, time dependent angular analysis of B${}_s^0\to$ J/$\psi$ K${}^{-}$K${}^{+}$ and ${\overline{B}}_s^0\to$ J/$\psi$ K${}^{-}$K${}^{+}$ decays is presented, using 2 fb${}^{-1}$ of proton-proton collision data, recorded by the LHCb experiment in 2015 and 2016. Besides the CP violating phase, also the lifetime splitting $\Delta {\Gamma }_s$ in the B${}_s^0$ meson system and the decay width difference, ${\Gamma }_s-{\Gamma }_d$, between B${}_s^0$ and B${}^0$ mesons is precisely measured. The results are combined with the corresponding LHCb Run I analysis.