Moments of Angular Distribution in Two Mesons Photoproduction

The formalism devoted to the production of two pseudoscalar mesons with a linearly polarized photon beam has been detailed and illustrated in Phys. Rev. D100 (2019) 054017. This document reports the necessary formulas, without proof, to perform an analysis of the angular distribution of two mesons photoproduction. The relations to extract moments of the angular distribution are provided, as well as the relations between moments and partial waves for a system involving $S$, $P$ and $D$ waves. The expressions of the integrated beam asymmetry and the beam asymmetry along the $y$ axis in term of moments are mentioned.