Nonleptonic decays of D- and K-mesons

Exclusive nonleptonic decays (D-Kπ, K-ππ) are discussed. The old standard model used factorization with vacuum insertion and disagrees with the D-Kπ experiments. Two proposed remedies, the annihilation model and the interference model are compared. We prove that annihilation graphs with arbitrary numbers of gluons, which were proposed to enhance D0-antiK π and K0sub(s)-ππ, are zero for K-ππ at the physical point, if the amplitudes are taken to be linear in the kinematic invariants. As a new tool we use valence quark topology in conjunction with soft π limits and current algebra