Search for the hyperon semileptonic decay $\hat{I}{ž}^{-}\to \hat{I}{ž}^0{e}^{-}\overline{\hat{I}{½}_e}$

Abstract

Using $(10.087\pm 0.044)\times 10^9$ $J/\ddot{I}ˆ$ events collected by the BESIII detector at the BEPCII collider, we search for the hyperon semileptonic decay $\hat{I}{ž}^{-}\to \hat{I}{ž}^0{e}^{-}\bar{\hat{I}}{½}_e$. No significant signal is observed and the upper limit on the branching fraction $\mathcal{B}(\hat{I}{ž}^{-}\to \hat{I}{ž}^0{e}^{-}\bar{\hat{I}}{½}_e)$ is set to be $2.59\times 10^{-4}$ at 90 % confidence level. This result is one order of magnitude more strict than the previous best limit.

8 pages, 3 figures