Momentum Dependent Vertices $\sigma \gamma \gamma$, $\sigma \rho \gamma$ and $\sigma \rho \rho$ : The NJL Scalar Hidden by Chiral Symmetry

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 $\sigma$.