A measurement of the Bs0→J/ψϕ 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) radΔΓs=0.053±0.021(stat)±0.010(syst) ps−1Γs=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) radwhere the parameter ΔΓs is constrained to be positive. The S-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.2 MoreReceived 8 July 2014DOI:https://doi.org/10.1103/PhysRevD.90.052007This article is available under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.© 2014 CERN, for the ATLAS Collaboration