First measurement of time-dependent $CP$ violation in the flavor-changing neutral-current decay $B^{0}\rightarrow K_{S}^{0}μ^{+}μ^{-}$

Abstract

A flavor-tagged time-dependent analysis of $B^{0}\rightarrow K_{S}^{0}μ^{+}μ^{-}$ decays is performed across the full dimuon mass range excluding the $J/ψ$ and $ψ(2S)$ resonance regions. The analysis uses proton-proton collision data collected by the LHCb experiment in 2011--2018 at center-of-mass energies of 7, 8 and 13TeV, corresponding to an integrated luminosity of 9$fb^{-1}$. The CP violation parameters are determined to be $C=-0.13 \pm 0.32 \pm 0.04$ and $S= +0.82\pm 0.29 \pm 0.05$, where the first uncertainties are statistical and the second are systematic. The results are consistent with the Standard Model prediction. This is the first experimental study of time-dependent CP violation in $b\rightarrow sl^{+}l^{-}$ processes.