Measurement of the $e^{+}e^{-}\rightarrowηπ^{+}π^{-}$ cross section with the CMD-3 detector at the VEPP-2000 collider
The cross section of the process $e^{+}e^{-}\rightarrowηπ^{+}π^{-}$ is measured using the data collected with the CMD-$3$ detector at the VEPP-$2000$ collider in the center-of-mass energy range from $1.1$ to $2.0$ GeV. The decay mode $η\rightarrowγγ$ is used for $η$ meson reconstruction in the data sample corresponding to an integrated luminosity of $78.3$ pb$^{-1}$. The energy dependence of the $e^{+}e^{-}\rightarrowηπ^{+}π^{-}$ cross section is fitted within the framework of vector meson dominance in order to extract the $Γ(ρ(1450)\rightarrow{^{+}e^{-}})\mathcal{B}(ρ(1450)\rightarrowηπ^{+}π^{-})$ and the $Γ(ρ(1700)\rightarrow{e^{+}e^{-}})\mathcal{B}(ρ(1700)\rightarrowηπ^{+}π^{-})$ products. Based on conservation of vector current, the analysed data are used to test the relationship between the $e^{+}e^{-}\rightarrowηπ^{+}π^{-}$ cross section and the spectral function in $τ^-\rightarrowηπ^-π^0ν_τ$ decay. The $e^{+}e^{-}\rightarrowηπ^{+}π^{-}$ cross section measured with the CMD-$3$ detector is in good agreement with the previous measurements.