Towards an improved understanding of $\eta \to {\gamma }^{\ast }{\gamma }^{\ast }$

S. Holz, J. Plenter, C. W. Xiao +5

We argue that high-quality data on the reaction $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\eta$ will allow one to determine the doubly-virtual form factor $\eta \to {\gamma }^{\ast }{\gamma }^{\ast }$ in a model-independent way with control…