$D^{*}D \rho $ vertex from QCD sum rules

Abstract

We calculate the form factors and the coupling constant in the $D^{*}D \rho $ vertex in the framework of QCD sum rules. We evaluate the three point correlation functions of the vertex considering both $ D $ and $ \rho $ mesons off--shell. The form factors obtained are very different but give the same coupling constant: $g_{D^{*}D \rho} = 4.1 \pm 0.1$ GeV$^{-1}$.