Search for the $\hat{I}{\cdot }^{\prime }\to e^{+}{e}^{-}$ decay with the SND detector

Abstract

A search for the process $e^{+}{e}^{-}\to \hat{I}{\cdot }^{\prime }$ has been performed with the SND detector at the VEPP-2000 $e^{+}{e}^{-}$ collider. The data were accumulated at the center-of-mass energy of $957.78\pm 0.06$ MeV with an integrated luminosity of about 2.9 pb${}^{-1}$. For reconstruction of the $\hat{I}{\cdot }^{\prime }$ meson five decay chains have been used: $\hat{I}{\cdot }^{\prime }\to \hat{I}\cdot \ddot{I}{€}^{+}\ddot{I}{€}^{-}$ followed by the $\hat{I}\cdot$ decays to ${\hat{I}}^3{\hat{I}}^3$ and $3\ddot{I}{€}^0$, and $\hat{I}{\cdot }^{\prime }\to \hat{I}\cdot \ddot{I}{€}^0\ddot{I}{€}^0$ followed by the $\hat{I}\cdot$ decays to $\ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0$, ${\hat{I}}^3{\hat{I}}^3$, and $3\ddot{I}{€}^0$. As a result, the upper limit has been set on the $\hat{I}{\cdot }^{\prime }$ electronic width: $\hat{I}{“}_{\hat{I}{\cdot }^{\prime }\to e^{+}{e}^{-}}<0.0020$ eV at the 90\% confidence level.

12 pages, 6 figures