Radiative decays of D mesons

Abstract

The short-distance contribution due to the $c\to uγ$ penguin as well as long-distance contributions are considered in an analysis of $D\to Vγ$ decays, the latter being dominant. The matrix elements for nine $D\to Vγ$ transitions are calculated using a hybrid model which combines heavy quark effective theory and the chiral Lagrangian. We present the expected range of the branching ratios for these decays, the most frequent ones $D^0\to \bar{K}^{*0}γ$ and $D^+_s \to ρ^+γ$, being a few times $10^{-4}$.