Measurement of $CP$ asymmetry in $D^0\to K_{\mathrm{S}}^0{K}_{\mathrm{S}}^0$ decays with Run 3 data

Abstract

A measurement of $CP$ asymmetry in $D^0\to K_{\mathrm{S}}^0{K}_{\mathrm{S}}^0$ decays is reported, based on a data sample of proton-proton collisions collected with the LHCb detector in 2024 at a centre-of-mass energy of $13.6$TeV, corresponding to an integrated luminosity of $6.2{\mathrm{fb}}^{-1}$. The $D^0\to K_{\mathrm{S}}^0\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ decay is used as calibration channel to cancel residual detection and production asymmetries. The time-integrated $CP$ asymmetry for the $D^0\to K_{\mathrm{S}}^0{K}_{\mathrm{S}}^0$ mode is measured to be $${\mathcal{A}}^{CP}(D^0\to K_{\mathrm{S}}^0{K}_{\mathrm{S}}^0)=(1.86\pm 1.04\pm 0.41)\%,$$ where the first uncertainty is statistical, and the second is systematic. This measurement represents the most precise single-experiment determination of this quantity to date.

All figures and tables, along with any supplementary material and additional information, are available at https://lbfence.cern.ch/alcm/public/analysis/full-details/4655