Measurement of the $e^+e^- \to ηπ^+π^-$ cross section with the SND detector at the VEPP-2000 collider

M. N. Achasov, A. Yu. Barnyakov, K. I. Beloborodov, A. V. Berdyugin, D. E. Berkaev, A. G. Bogdanchikov, A. A. Botov, T. V. Dimova, V. P. Druzhinin, V. B. Golubev, L. V. Kardapoltsev, A. G. Kharlamov, I. A. Koop, A. A. Korol, D. P. Kovrizhin, S. V. Koshuba, A. S. Kupich, A. P. Lysenko, K. A. Martin, N. A. Melnikova, N. Yu. Muchnoi, A. E. Obrazovsky, E. V. Pakhtusova, E. A. Perevedentsev, K. V. Pugachev, E. V. Rogozina, S. I. Serednyakov, Z. K. Silagadze, Yu. M. Shatunov, P. Yu. Shatunov, D. A. Shtol, I. K. Surin, Yu. A. Tikhonov, Yu. V. Usov, A. V. Vasiljev, I. M. Zemlyansky

Published 2017-11-24Version 1

The $e^+e^- \to \eta\pi^+\pi^-$ cross section is measured at the SND detector in the $\eta$ decay mode $\eta\to 3\pi^0$. The analysis is based on the data sample with an integrated luminosity of 32.7 pb$^{-1}$ collected at the VEPP-2000 $e^+e^-$ collider in the center-of-mass energy range $\sqrt{s}=1.075-2.000$ GeV. The data obtained in the $\eta\to 3\pi^0$ decay mode are found to be in agreement with the previous SND measurements in the $\eta\to \gamma\gamma$ mode. Therefore the measurements in the two modes are combined.