A formalism for the study of $K^{+}\pi\,\Sigma$ photoproduction in the $\Lambda^{\ast}(1405)$ region

Abstract

We present a formalism for the low-energy analysis of the $\gamma p\rightarrow K^{+}\pi\Sigma$ photoproduction reaction in the $\Lambda^{\ast}(1405)$ resonance region. In particular, the constraints arising from unitarity, gauge invariance and chiral perturbation theory are discussed in some detail.