Flavor symmetry, K0–K̄0 mixing and new physics effects on CP violation in D± and D±s decays

Flavor symmetry and symmetry breaking, K0–K̄0 mixing and possible effects of new physics on CP violation in weak decay modes D±→KS,L+X±, (KS,L+π0)K∗+X± (for X=π,ρ,a1) and D±s→KS,L+X±s, (KS,L+π0)K∗+X±s (for Xs=K,K∗) are analyzed. Relations between D± and D±s decay branching ratios are obtained from the d⇔s subgroup of SU(3) and dominant symmetry-breaking mechanisms are investigated. A CP asymmetry of magnitude 3.3×10−3 is shown to result in the standard model from K0–K̄0 mixing in the final-state. New physics affecting the doubly Cabibbo-suppressed channels might either cancel this asymmetry or enhance it up to the percent level. A comparison between the CP asymmetries in D±(s)→KSX±(s) and D±(s)→KLX±(s) can pin down effects of new physics.