Measurement of the $e^{+}{e}^{-}\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0\hat{I}\cdot$ cross section below $\sqrt{s}=2$ GeV

Abstract

The process $e^{+}{e}^{-}\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0\hat{I}\cdot$ is studied in the center-of-mass energy region below 2 GeV with the SND detector at the VEPP-2000 $e^{+}{e}^{-}$ collider. The four intermediate states contribute to this process: $\ddot{I}‰\hat{I}\cdot$, $\ddot{I}•\hat{I}\cdot$, $a_0(980)\ddot{I}$, and a structureless $\ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0\hat{I}\cdot$ state. We measure the total $e^{+}{e}^{-}\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0\hat{I}\cdot$ cross section and the cross sections for its components: $\ddot{I}‰\hat{I}\cdot$, $\ddot{I}•\hat{I}\cdot$, and a sum of $a_0(980)\ddot{I}$ and the structureless state. Our results are in agreement with previous measurements and have comparable or better accuracies.

17 pages, 11 figures, 3 tables. arXiv admin note: text overlap with arXiv:1607.00371