The rare decay $η\toππγγ$ in chiral perturbation theory

Abstract

We investigate the rare radiative eta decay modes $η\toπ^+π^-γγ$ and $η\toπ^0π^0γγ$ within the framework of chiral perturbation theory at $O(p^4)$. We present photon spectra and partial decay rates for both processes as well as a Dalitz contour plot for the charged decay.

26 pages, RevTex, 10 figures, to appear in Phys. Rev. D