Fig. 5.

Illustration of the background estimation using the $Z\to ee\mathit{\gamma }$ method in the 10 $\text{GeV}$ < $E_{\mathrm{T}}$ < 15 $\text{GeV}$, 0.1 < $|\mathit{\eta }|$ < 0.8 bin, at reconstruction + track-quality level (left) and for probe electron candidates passing the cut-based Tight identification (right). The background template is normalized in the range 100 $\text{GeV}$ < $m_{ee}$ < 250 $\text{GeV}$. The tag electron passes cut-based Medium and isolation requirements. The signal MC simulation is scaled to match the estimated signal in the $Z$-mass window