The problems of $\eta'\rightarrow\pi^0\gamma\gamma$ decay and the New Physics.
BES-III Collaboration reported the observation of the rare decay $\eta'\rightarrow\pi^0\gamma\gamma$. The observed decay width sharply disagrees with the preliminary theoretical estimations. 
The aim of our paper is to reduce the theoretical uncertainty by taking the coupling constants extracted from the known meson decays without any assumptions. For the L$\sigma$M(ChPT) contributions we consider several values of the mixing angles extracted in different ways thus making our predictions more solid. 
We show that both our result and the preliminary estimations disagree with the BES-III result. 
We consider several possible explanations of this discrepancy including the New Physics.