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Regular version of the site

Article

Measurement of the CP-violating phase ϕs and the B0s meson decay width difference with B0s→J/ψϕ decays in ATLAS

Journal of High Energy Physics. 2016. Vol. 8. No. 147. P. 1-44.
A. Maevskiy, A. S. Boldyrev, ATLAS C.

A measurement of the B s 0 decay parameters in the B s 0  → J/ψϕ channel using an integrated luminosity of 14.3 fb−1 collected by the ATLAS detector from 8 TeV pp collisions at the LHC is presented. The measured parameters include the CP -violating phase ϕ s , the decay width Γ sand the width difference between the mass eigenstates ΔΓ s . The values measured for the physical parameters are statistically combined with those from 4.9 fb−1 of 7 TeV data, leading to the following:

𝜙𝑠=−0.090±0.078(stat.)±0.041(syst.)rad

𝛥𝛤𝑠=0.085±0.011(stat.)±0.007(syst.)ps−1

𝛤𝑠=0.675±0.003(stat.)±0.003(syst.)ps−1.

In the analysis the parameter ΔΓ s is constrained to be positive. Results for ϕ s and ΔΓ s are also presented as 68% and 95% likelihood contours in the ϕ s -ΔΓ s plane. Also measured in this decay channel are the transversity amplitudes and corresponding strong phases. All measurements are in agreement with the Standard Model predictions.