Measurement of CP Violation in D⁰ Meson Decays at the CMS Experiment

The paper describes the search results for CP violation in the D⁰ → \(K_{S}^{0}K_{S}^{0}\) decay. The analysis was performed using the proton–proton collision data with centre-of-mass energy of \(\sqrt s \) = 13 TeV, recorded by the CMS experiment at the Large Hadron Collider. The analyzed data sample contains about 10¹⁰ events associated with production of charm hadrons, which allows performing precise measurements. The measured CP violation parameter is A_CP (D⁰ → \(K_{S}^{0}K_{S}^{0}\) ) = (6.2 ± 3.1 (stat.) ± 0.2 (syst.) ± 0.8 (A_CP (D⁰ → \(K_{S}^{0}\) π⁺π⁻))%, where the last uncertainty is due to the uncertainty in the reference channel asymmetry A_CP (D⁰ → \(K_{S}^{0}\) π⁺π⁻). The obtained results are consistent with no CP violation in the studied decay. This analysis is the first measurement of CP violation in charm sector at the CMS experiment.