Measurement of $C\text{\hspace{0.17em}⁣}P$ asymmetry in $D^0\to K_{\mathrm{S}}^0{K}_{\mathrm{S}}^0$ decays with Run 3 data

A measurement of $C\text{\hspace{0.17em}⁣}P$ 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 $6.2{\mathrm{f}\mathrm{b}}^{-1}$. The $D^0\to K_{\mathrm{S}}^0{\pi }^{+}{\pi }^{-}$ decay is used as calibration channel to cancel residual detection and production asymmetries. The time-integrated $C\text{\hspace{0.17em}⁣}P$ asymmetry for the $D^0\to K_{\mathrm{S}}^0{K}_{\mathrm{S}}^0$ mode is measured to be $${\mathcal{A}}^{C\text{\hspace{0.17em}⁣}P}(D^0\to K_{\mathrm{S}}^0{K}_{\mathrm{S}}^0)=(1.86\pm 1.04\pm 0.41)\mathrm{\%},$$ 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.