Measurement of the $e^{+}{e}^{-}\to K^{+}{K}^{-}\ddot{I}{€}^0$ cross section with the SND detector

Abstract

The process $e^{+}{e}^{-}\to K^{+}{K}^{-}\ddot{I}{€}^0$ is studied with the SND detector at the VEPP-2000 $e^{+}{e}^{-}$ collider. Basing on data with an integrated luminosity of 26.4~pb${}^{-1}$ we measure the $e^{+}{e}^{-}\to K^{+}{K}^{-}\ddot{I}{€}^0$ cross section in the center-of-mass energy range from 1.28 up to 2 GeV. The measured mass spectrum of the $K\ddot{I}€$ system indicates that the dominant mechanism of this reaction is the transition through the $K^{\ast }(892)K$ intermediate state. The cross section for the $\ddot{I}•\ddot{I}{€}^0$ intermediate state is measured separately. The SND results are consistent with previous measurements in the BABAR experiment and have comparable accuracy. We study the effect of the interference between the $\ddot{I}•\ddot{I}{€}^0$ and $K^{\ast }K$ amplitudes. It is found that the interference gives sizable contribution to the measured $e^{+}{e}^{-}\to \ddot{I}•\ddot{I}{€}^0\to K^{+}{K}^{-}\ddot{I}{€}^0$ cross section below 1.7 GeV.