. Invariant-mass distribution of correlated electron-hadron and hadron-hadron pairs, where hadrons are wrongly identified as electrons, in comparison with the invariant-mass spectrum of all pairs (dielectron signal pairs and `contaminated' pairs) obtained from MC simulations. In the bottom panel, the ratio between the invariant-mass spectrum of electron-hadron and hadron-hadron pairs to that of all pairs is shown. Boxes represent the systematic uncertainties on the hadron contamination.