CP Asymmetries In D Decays Into Neutral Kaons

CP violation is a crucial element to interpret the matter-antimatter asymmetry in the Universe.D mesons as the lightest particles with heavy quark,their CP asymmetries are unique in searching for new physics.The CP asymmetries in the D meson decays into neutral kaons are studied in this work.We find a new CP-violating effect that results from the interference between two tree(Cabibbo-favored and doubly Cabibbo-suppressed)am-plitudes with the mixing of final-state mesons.The time-dependent and time-integrated CP asymmetries in the D?KS,L0 P(V)(where P(V)denotes a pseudoscalar(vector)me-son)modes are analyzed in the factorization-assisted topological amplitude approach.The new-found effect is of order of O(10-4?-3),which is much larger than the direct violation induced by the interference between the Cabibbo-favored and doubly Cabibbo-suppressed amplitudes.We suggest to measure the difference between the CP asymmetries in the D+?KS0?+ and Ds+? KS0K+ modes to extract the new CP-violating effect.The direct CP violation of D meson decays into neutral kaons is sensitive to the new physics.It could be enhanced to observable level even if the new physics amplitudes are two or three order smaller than the doubly Cabibbo-suppressed amplitudes in the Standard Model.Taking the Left-Right Symmetric Model as an example,we find the direct CP asymmetries could reach to be O(10-3)and then could be used to search for new physics.Compared to the singly Cabibbo-suppressed decays,the CP asymmetries in D meson decays into neutral kaons could provide a clear new physics signal since all amplitudes are at tree level.