CP violation Measurements with the ATLAS Detector

The ATLAS experiment at the Large Hadron Collider measures CP violation in the neutral Bs meson system through the exclusive decay Bs to J/psi phi by analysing time dependent angular correlations of the final state. With 4.9 fb^-1 of integrated luminosity recorded in 2011 in pp collisions at the LHC at a centre of mass energy of sqrt(s) = 7 TeV first ATLAS results on the values of the CP-violating phase phi_s, the decay width difference Delta_Gamma_s as well as other physics parameters of the Bs meson decay have been obtained and will be presented here.