$CP$ violation in $B_s^0\rightarrow J/\psi \phi$ in the ATLAS experiment

The measurement of the $CP$-violation parameters in the $B_s^0\rightarrow J/\psi(\mu^+\mu^-)\phi(K^+ K^-)$ channel using data collected by the ATLAS detector from 13 TeV pp collisions at the LHC with integrated luminosity of 80.5 fb$^{-1}$ is presented. The measured parameters include the CP-violating phase $\phi_s$ and the width difference $\Delta\Gamma_s$ between the $B_s^0$ meson mass eigenstates, which can be compared with the Standard Model prediction. Furthermore the average decay width $\Gamma_s$, transversity amplitudes and corresponding strong phases are measured. The measured values are then combined with those from 19.2 fb$^{-1}$ of 7 TeV and 8 TeV data. All measurements are in agreement with the Standard Model predictions and other LHC measurements.