Flavor tagged time-dependent angular analysis of the B0 s → J/ψ ϕ decay and extraction of ΔΓs and the weak phase ϕs in ATLAS

A measurement of the B0 s → J/ψ ϕ decay parameters, updated to include flavor tagging, is reported using 4.9 fb−1 of integrated luminosity collected by the ATLAS detector from √s=7 TeV pp collisions recorded in 2011 at the LHC. The values measured for the physical parameters are ϕs= 0.12+-0.25(stat)+-0.05(syst) rad , ΔΓs = 0.053+-0.021(stat)+-0.010(syst)ps^−1, Γs= 0.677+-0.007(stat)+-0.004(syst) ps^−1, A∥(0)^2 =0.220+-0.008(stat)+-0.009(syst), A0(0)^2 = 0.529+-0.006(stat)+-0.012(syst), δ⊥ = 3.89+-0.47(stat)+-0.11(syst) rad where the parameter ΔΓs is constrained to be positive.TheS-wave contribution was measured and found to be compatible with zero. Results for ϕs and ΔΓs are also presented as 68% and 95% likelihood contours, which show agreement with the Standard Model expectations.