Fig. 16.

Distribution of the invariant mass $m_{ee}$ of the selected opposite-sign (OS) or same-sign (SS) electron pairs in data and MC simulation for 25 $\text{GeV}$ < $E_{\mathrm{T}}$ < 50 $\text{GeV}$ in the 0.0 < $\mathit{\eta }$ < 0.8 bin (left) and in the 2.0 < $\mathit{\eta }$ < 2.47 bin (right). Tag and probe electron candidates are required to pass the cut-based Tight identification and a track isolation requirement of $p_{\mathrm{T}}^{\mathrm{cone}0.2}/E_{\mathrm{T}}<0.14$