negligible contribution.

In the case of the ${\ensuremath{\PH \to 4\ell}\xspace}$ cross section measurements, the irreducible $\PQq\PAQq \to \Z\Z$ and $\Pg\Pg \to \Z\Z$ backgrounds are evaluated from simulation based on generators discussed in Section \[sec:DatasetsSimulationPAS\], following Ref. [@Chatrchyan:2013mxa]. In the case of the $\Pg\Pg \to \Z\Z$ background, the LO cross section of $\Pg\Pg \to \Z\Z$ is corrected via a $m_{4\ell}$ dependent k-factor, as recommended in the study of Ref. [@Bonvini:2013].

[l|ccc]{} Channel & $4\Pe$ & $4\Pgm$ & $2\Pe2\Pgm$\
\
\
$\PQq\PAQq \to \PZ\PZ$ & 0.8 $\pm$ 0.1 & 1.8 $\pm$ 0.1 & 2.2 $\pm$ 0.3\
$\PZ+\mathrm{X}$ & 0.3 $\pm$ 0.1 & 0.2 $\pm$ 0.1 & 1.0 $\pm$ 0.3\
$\Pg\Pg \to \PZ\PZ$ & 0.03 $\pm$ 0.01 & 0.06 $\pm$ 0.02 & 0.07 $\pm$ 0.02\
Total background expected & 1.2 $\pm$ 0.1 & 2.1 $\pm$ 0.1 & 3.4 $\pm$ 0.4\
${\ensuremath{\PH \to 4\ell}\xspace}$ ($m_{\PH} = 125.0\GeV$) & 0.7 $\pm$ 0.1 & 1.2 $\pm$ 0.1 & 1.7 $\pm$ 0.3\
Observed & 1 & 3 & 6\
\
\
$\PQq\PAQq \to \PZ\PZ$ & 3.0 $\pm$ 0.4 & 7.6 $\pm$ 0.5 & 9.0 $\pm$ 0.7\
$\PZ + \mathrm{X}$ & 1.5 $\pm$ 0.3 & 1.2 $\pm$ 0.5 & 4.2 $\pm$ 1.1\
$\Pg\Pg \to \PZ\PZ$ & 0.2 $\pm$ 