(a) Distribution of $d_{\mathrm 0} \times$ charge for electron candidates after all analysis cuts (except that on $d_{\mathrm 0}$) superimposed to the best-fit result. The fit function is defined as the sum of the Monte Carlo $d_{\mathrm 0}$ distribution of beauty electrons and those of electrons from all other sources, the normalizations being the free parameters in the fit. The error bars represent the statistical uncertainties (b) Differences between the data and the best fit result divided by the statistical error. |