Search for the semileptonic decay $D_s^{+}\to \ddot{I}{€}^0{e}^{+}\hat{I}{½}_e$

Abstract

We present the first search for the semileptonic decay $D_s^{+}\to \ddot{I}{€}^0{e}^{+}\hat{I}{½}_e$ using a data sample of electron-positron collisions recorded with the BESIII detector at center-of-mass energies between 4.178 and 4.226~GeV, corresponding to an integrated luminosity of 6.32~fb${}^{-1}$. This decay is expected to be sensitive to $\ddot{I}{€}^0$--$\hat{I}\cdot$ mixing. No significant signal is observed. We set an upper limit of $6.4\times 10^{-5}$ on the branching fraction at the $90\%$ confidence level.

10 pages, 6 figures