Towards a high precision CP violation measurement with the ATLAS Detector

ATLAS is a general purpose detector designed to study the high energy proton-proton collisions produced at the Large Hadron Collider. The channel Bs→J/ψφ offers a measurement of standard model CP violating parameters, and has the potential to be sensitive to new physics. The measurement of CP violation in the Bs→J/ψφ channel at ATLAS is largely determined by three factors: statistics, lifetime resolution and flavour tagging. This study concentrates on improving the lifetime measurement and the implementation of flavour tagging. Flavour tagging has a strong influence on the sensitivity of CP violation studies. The jet charge flavour tagging method was optimised to increase its effectiveness. The lifetime of a B-hadron is calculated using the pT , mass and vertexing. A deformation in the inner detector can produce a detectable change in these observables.