Invariant mass (left panel) and pseudoproper decay length (right panel) distributions of opposite sign electron pairs for $|y_{\rm J/\psi}|< 0.9$ and $p_{\rm t}^{\rm J/\psi} > 1.3$ GeV/$c$ with superimposed projections of the maximum likelihood fit. The latter distribution is limited to the $\jpsi$ candidates under the mass peak, i.e. for $2.92 < m_{\rm e^+ e^-} < 3.16$ GeV/$c^2$, for display purposes only. The $\chi^2$ values of these projections are reported for both distributions.