Measurement of the CP-violating phase $$\phi _s$$ in $$B_{s}^{0} \rightarrow J/\psi \phi$$ decays in ATLAS at 13 TeV
Abstract A measurement of the $$B_{s}^{0} \rightarrow J/\psi \phi$$ B s 0 → J / ψ ϕ decay parameters using $$80.5\, \mathrm {fb^{-1}}$$ 80.5 fb - 1 of integrated luminosity collected with the ATLAS detector from 13  $$\text {Te}\text {V}$$ Te proton–proton collisions at the LHC is presented. The measured parameters include the CP -violating phase $$\phi _{s}$$ ϕ s , the width difference $$\Delta \Gamma _{s}$$ Δ Γ s between the $$B_{s}^{0}$$ B s 0 meson mass eigenstates and the average decay width $$\Gamma _{s}$$ Γ s . The values measured for the physical parameters are combined with those from $$19.2\, \mathrm {fb^{-1}}$$ 19.2 fb - 1 of 7 and 8  $$\text {Te}\text {V}$$ Te data, leading to the following: \begin{aligned} \phi _{s}= & {} -0.087 \pm 0.036 ~\mathrm {(stat.)} \pm 0.021 ~\mathrm {(syst.)~rad} \\ \Delta \Gamma _{s}= & {} 0.0657 \pm 0.0043 ~\mathrm {(stat.)}\pm 0.0037 ~\mathrm {(syst.)~ps}^{-1} \\ \Gamma _{s}= & {} 0.6703 \pm 0.0014 ~\mathrm {(stat.)}\pm 0.0018 ~\mathrm {(syst.)~ps}^{-1} \end{aligned} ϕ s = - 0.087 ± 0.036 ( stat . ) ± 0.021 ( syst . ) rad Δ Γ s = 0.0657 ± 0.0043 ( stat . more »