Measurement of the CP-violating phase ₛ in the B⁰ₛ J/ decay with the ATLAS detector

In the presence of New Physics phenomena, sources of CP violation can arise in addition to those predicted by the Standard Model. The Bₛ⁰ J/ decay can provide a very precise measurement of the CP-violating phase ₛ, the decay width ₛ and the difference of widths between the mass eigenstates ₛ. Results presented here use data of pp collisions at s = 13 TeV corresponding to 80. 5 fb^-1 of integrated luminosity collected by ATLAS at the Large Hadron Collider in years 2015--2017, and are statistically combined with the previous measurements with 19. 2~fb^-1 data with 7 and 8~TeV energy leading to align* ₛ &= -0. 087 0. 036 (stat. ) 0. 021 (syst. ) \\ ₛ &= 0. 6703 0. 0014 (stat. ) 0. 0018 (syst. ) \\ ₛ &= 0. 0657 0. 0043 (stat. ) 0. 0037 (syst. ). \\ align*