Limits on neutral $D$ mixing in semileptonic decays

Using the CLEO II.V detector observing $e^{+}{e}^{-}$ collisions at around 10.6 GeV we search for neutral $D$ mixing in semileptonic $D^0$ decays tagged in charged $D^{*}$ decays. Combining the results from the $Ke\nu$ and $K^{*}e\nu$ channels we find that the rate for $D$ mixing is less than 0.0078 at $90\%$ C.L.

Figure 1

The output of the neural net used in the $D^0\to Ke\nu$ analysis for the RS (left) and WS (right) samples comparing data (squares) with simulation (full histogram). Also shown with a dashed histogram is the predicted contribution of the signal. The very small WS signal is at the central value found by this analysis.

Figure 2

The decay time for the $D^0\to Ke\nu$ analysis for the RS (left) and WS (right) samples. The squares show the data, the full histogram shows the fits, and the dashed histogram the signal contribution to the fits.

Figure 3

The $Q$ (top) and decay time (bottom) distributions for the $D^0\to K^{*}e\nu$ analysis for the RS sample. The squares show the data, the histograms show projections of the two dimensional fit, and the dashed histogram shows the background contribution to the fit.

Figure 4

The $Q$ (top) and decay time (bottom) distributions for the $D^0\to K^{*}e\nu$ analysis for the WS sample. The squares shows the data and the histograms shows projections of the two dimensional fit.