Study of the process $e^{+}{e}^{-}\to K^{+}{K}^{-}\hat{I}\cdot$ with the CMD-3 detector at the VEPP-2000 collider

Abstract

The process $e^{+}{e}^{-}\to K^{+}{K}^{-}\hat{I}\cdot$ has been studied in the center-of-mass energy range from 1.59 to 2.007\,GeV using the data sample of 59.5 pb${}^{-1}$, collected with the CMD-3 detector at the VEPP-2000 $e^{+}{e}^{-}$ collider in 2011, 2012 and 2017. The $K^{+}{K}^{-}\hat{I}\cdot$ final state is found to be dominated by the contribution of the $\ddot{I}•(1020)\hat{I}\cdot$ intermediate state. The cross section of the process $e^{+}{e}^{-}\to \ddot{I}•(1020)\hat{I}\cdot$ has been measured with a systematic uncertainty of 5.1$\%$ on the base of 3009 $\pm$ 67 selected events. The obtained cross section has been used to calculate the contribution to the anomalous magnetic moment of the muon: $a_{\hat{I}}{¼}^{\ddot{I}•\hat{I}\cdot }(E<1.8\mathrm{GeV})=(0.321\pm 0.015_{\mathrm{stat}}\pm 0.016_{\mathrm{syst}})\times 10^{-10}$, $a_{\hat{I}}{¼}^{\ddot{I}•\hat{I}\cdot }(E<2.0\mathrm{GeV})=(0.440\pm 0.015_{\mathrm{stat}}\pm 0.022_{\mathrm{syst}})\times 10^{-10}$. From the cross section approximation the $\ddot{I}•(1680)$ meson parameters have been determined with better statistical precision, than in previous studies.