New Modes: D+s → ρ+γ, D+ → Κ*+γ, and weak annihilation

A class of decay modes sensitive to only one quark topology at leading GF order (annihilation of valence quarks through a W) is described. No experimental observations, nor even upper limits, have been reported for these decays. This work represents a simpleminded (order-of-magnitude) first calculation of their branching fractions. Although rare, one of these modes D+s → ρ+γ might already be observable at charm experiments, while another D+ → Κ*+γ should appear at the B factories, and the rest at hadron colliders