Tests of isospin symmetry breaking at $\varphi (1020)$ meson factories

H. Genz, S. Tatur

In a model of isospin symmetry breaking we obtain the ($e^{-}{e}^{+}\to {\pi }^{-}{\pi }^{+}$) amplitude $Q$ and the isospin $I=0$ and $I=1$ relative phase $\psi$ at the $\varphi (1020)$ reso…