Scalar $a_0(980)$ meson in $\varphi \to {\pi }^0\eta \gamma$ decay

We study the radiative decay $\varphi \to {\pi }^0\eta \gamma$ within the framework of a phenomenological approach in which the contributions of $\rho$-meson, chiral loop and $a_0$-meson are considered. We analyze the interference effects between different contributions and utilizing the experimental branching ratio and invariant ${\pi }^0\eta$ mass spectrum for $\varphi \to {\pi }^0\eta \gamma$ decay we estimate the branching ratio of $\varphi \to a_0\gamma$ decay.