Measurement of ∆Γs and the CP-violating weak phase φs in the decay Bs0→J/ψφ by ATLAS

A measurement of Bs0 → J/ψφ decay parameters, including the CP-violating weak phase φs and the decay width difference ∆Γs is reported, using 4.9 fb−1 of integrated luminosity collected in 2011 by the ATLAS detector. The measured parameters are consistent with the world average values and with theoretical expectations, in particular φs is within 1σ of the expected value in the Standard Model.