A bstract A measurement of CP asymmetry in D⁰ Kₒ⁰Kₒ⁰ D 0 → K S 0 K 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 fb − 1. The D⁰ Kₒ⁰^+^- D 0 → K S 0 π + π − decay is used as calibration channel to cancel residual detection and production asymmetries. The time-integrated CP asymmetry for the D⁰ Kₒ⁰Kₒ⁰ D 0 → K S 0 K S 0 mode is measured to be A^CP (D⁰ Kₒ⁰Kₒ⁰) = (1. 86 1. 04 0. 41) \%, A CP D 0 → K S 0 K S 0 = 1. 86 ± 1. 04 ± 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.
Aaij et al. (Thu,) studied this question.