Table 2.

The preselection criteria for the three analysis channels

Selection criteria	$2{\ell }^{\text{ss}}$	$3\ell$	$4\ell$
Trigger	At least one lepton with $p_{\mathrm{T}}^{\ell }>30$ GeV that fulfils the requirements of single-lepton triggers
$N_{\ell }$(L-type, $p_{\mathrm{T}}>10$ GeV, $|{\eta }_{\ell }|<2.47$)	2	3	4
$N_{\ell }$(T-type, $p_{\mathrm{T}}>10$ GeV, $|{\eta }_{\ell }|<2.47$)	2	2 (${\ell }_{1,2}$)	−
$|\sum Q_{\ell }|$	2	1	0
Lepton $p_{\mathrm{T}}$ threshold	$p_{\mathrm{T}}^{{\ell }_1,{\ell }_2}>30,20$ GeV	$p_{\mathrm{T}}^{{\ell }_0,{\ell }_1,{\ell }_2}>10,20,20$ GeV	$p_{\mathrm{T}}^{{\ell }_1,{\ell }_2,{\ell }_3,{\ell }_4}>10$ GeV
$E_{\text{T}}^{\text{miss}}$	$>70$ GeV	$>30$ GeV	$>30$ GeV
$N_{\text{jets}}$	$\ge 3$	$\ge 2$	–
b-jet veto	$N_{b\text{-jet}}=0$	$N_{b\text{-jet}}=0$	$N_{b\text{-jet}}=0$
Low SFOS $m_{\ell \ell }$ veto	–	$m_{{\ell }^{\pm }{\ell }^{\mp }}>15\text{GeV}$	$m_{{\ell }^{\pm }{\ell }^{\mp }}>12\text{GeV}$
Z boson decays veto	$|m_{e^{\pm }{e}^{\pm }}-m_Z|>10\text{GeV}$	$|m_{{\ell }^{\pm }{\ell }^{\mp }}-m_Z|>10\text{GeV}$

The leptons are ordered by decreasing $p_{\mathrm{T}}$ (${\ell }_1,{\ell }_2,\dots$) in the $2{\ell }^{\text{ss}}$ and $4\ell$ channels, while for the $3\ell$ channel ${\ell }_1,{\ell }_2$ denote the same-sign leptons and ${\ell }_0$ the lepton with a charge opposite to the total lepton charge. $Q_{\ell }$ denotes the charge of each lepton