Determination of the $CP$-violating phase $\phi_s$ in $B0s \to J\psi \Phi$ decays

The determination of the CP-violating phase $\phi_{s}$ in $B^{0}_{s}\rightarrow J/\psi \phi$ decays is one of the key goals of the LHCb experiment. Its value is predicted to be very small in the Standard Model. However it can be significantly enhanced by contributions from effects of new physics. The most precise measurements of $\phi_{s}$ and $\Delta\Gamma_{s}$ to date are presented. Using a dataset corresponding to 3 fb$^{-1}$ collected at LHCb during 2011-2012 they are measured to be $\phi_{s}=-0.010\pm0.039$ rad and ${\Delta\Gamma_{s}}=0.0805\pm0.0091\pm0.0032$ ps$^{-1}$. $\text {PACS numbers: 11.30.Hv, 13.20.Fc, 14.40.Lb}$