Search for $\hat{I}\cdot$ and $\hat{I}{\cdot }^{\prime }\to \ddot{I}{€}^{+}{e}^{-}\bar{\hat{I}}{½}_e+c.c.$ decays in $\jpsi \to ϕη$ and $\ddot{I}•\hat{I}{\cdot }^{\prime }$

Abstract

Using a sample of 225.3 million $\jpsi$ events collected with the BESIII detector at the BEPCII $e^{+}{e}^{-}$ collider in 2009, searches for the decays of $\hat{I}\cdot$ and $\hat{I}{\cdot }^{\prime }\to \ddot{I}{€}^{+}{e}^{-}\bar{\hat{I}}{½}_e+c.c.$ in $\jpsi \to ϕη$ and $\ddot{I}•\hat{I}{\cdot }^{\prime }$ are performed. The $\ddot{I}•$ signals, which are reconstructed in $K^{+}{K}^{-}$ final states, are used to tag $\hat{I}\cdot$ and $\hat{I}{\cdot }^{\prime }$ semileptonic decays. No signals are observed for either $\hat{I}\cdot$ or $\hat{I}{\cdot }^{\prime }$, and upper limits at the 90% confidence level are determined to be $7.3\times 10^{-4}$ and $5.0\times 10^{-4}$ for the ratios $\frac{{\mathcal B}(η\to π^+ e^- \barν_e +c.c.)}{{\mathcal B}(η\to \pip\pim\piz)}$ and $\frac{{\mathcal B}(η^\prime\to π^+ e^-\barν_e +c.c.)}{{\mathcal B}(η^\prime \to \pip\pimη)}$, respectively. These are the first upper limit values determined for $\hat{I}\cdot$ and $\hat{I}{\cdot }^{\prime }$ semileptonic weak decays.

8 pages, 4 figures; version accpeted for publication at PRD