Search for hyperon $\hat{I}”S=\hat{I}”Q$ violating decay $\hat{I}{ž}^0\to \hat{I}{\pounds }^{-}{e}^{+}\hat{I}{½}_e$

Abstract

Using a data sample of $(1.0087\pm 0.0044)\times 10^{10}$ $J/\ddot{I}ˆ$ decay events collected with the BESIII detector at the center-of-mass energy of $\sqrt{s}=3.097$ GeV, we present a search for the hyperon semileptonic decay $\hat{I}{ž}^0\to \hat{I}{\pounds }^{-}{e}^{+}\hat{I}{½}_e$ which violates the $\hat{I}”S=\hat{I}”Q$ rule. No significant signal is observed, and the upper limit on the branching fraction $\mathcal{B}(\hat{I}{ž}^0\to \hat{I}{\pounds }^{-}{e}^{+}\hat{I}{½}_e)$ is determined to be $1.6\times 10^{-4}$ at the 90% confidence level. This result improves the previous upper limit result by about one order of magnitude.

9 pages, 4 figures