Momentum Dependent Vertices $σγγ$, $σργ$ and $σρρ$ : The NJL Scalar Hidden by Chiral Symmetry

Abstract

We calculate the momentum dependence of three particle vertices $σγγ$, $σργ$ and $σρρ$ in the context of a Nambu Jona Lasinio type model. We show how they influence the processes $γγ\rightarrow σ\rightarrow ππ$, $ρ\rightarrow γσ$ and $γγ\rightarrow ρρ$ and how chiral symmetry shadows the presence of the $σ$.