  We calculate the momentum dependence of three particle vertices $\sigma
\gamma \gamma$, $\sigma \rho \gamma$ and $\sigma \rho \rho$ in the context of a
Nambu Jona Lasinio type model. We show how they influence the processes $\gamma
\gamma \rightarrow \sigma \rightarrow \pi \pi$, $\rho \rightarrow \gamma
\sigma$ and $\gamma \gamma \rightarrow \rho \rho$ and how chiral symmetry
shadows the presence of the $\sigma$.
