Measurement of the e+e−→ ηπ+π− cross section with the CMD-3 detector at the VEPP-2000 collider

Abstract

The cross section of the process e⁺e⁻→ ηπ⁺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 → γγ 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⁻→ ηπ⁺π⁻ cross section is fitted within the framework of vector meson dominance in order to extract the Γ(ρ(1450) → e⁺e⁻)$\mathcal{B}$(ρ(1450) → ηπ⁺π⁻) and the Γ(ρ(1700) → e⁺e⁻)$\mathcal{B}$(ρ(1700) → ηπ⁺π⁻) products. Based on conservation of vector current, the analyzed data are used to test the relationship between the e⁺e⁻→ ηπ⁺π⁻ cross section and the spectral function in τ⁻→ ηπ⁻π⁰ντ decay. The e⁺e⁻→ ηπ⁺π⁻ cross section obtained with the CMD-3 detector is in good agreement with the previous measurements.