Radiative decays of D mesons

Abstract

The short-distance contribution due to the $c\to u\gamma$ penguin as well as long-distance contributions are considered in an analysis of $D\to V\gamma$ decays, the latter being dominant. The matrix elements for nine $D\to V\gamma$ 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 $D^0\to {\bar{K}}^{\ast 0}\gamma$ and $D_s^{+}\to {\rho }^{+}\gamma$, being a few times $10^{-4}$.

Comments: 3 pages, latex; corrected the values in Table 1; Talk given by P. Singer at the Hyperons, Charm and Beauty Hadrons, Genova, Italy, 30 June -3 July 1998, to appear as proceedings in Nucl. Phys. B