Strong phases, asymmetries, and SU(3) symmetry breaking in D --> K pi decays

Motivated by some new experimental data, we carry out a phenomenological analysis of D --> K pi decays including both Cabibbo favored and doubly Cabibbo suppressed modes. Two asymmetries, R(D^0) and R(D+), which are generated through interference between Cabbibo favored and doubly Cabibbo suppressed D --> K pi transitions, are predicted. The relative strong phase, delta_{K pi}, between D^0 --> K- pi+ and D^0 --> K+ pi- decays, is estimated. The theoretical results agree well with the current measurements.