requirement on the $m_{4\ell}$ is important as the off-shell production cross section in the dominant gluon fusion production mode is sizeable and can amount up to a few percent of the total cross section [@Kauer:2012hd]. All the requirements and selections used in the definition of the fiducial phase space are summarised in Table \[tab:FidDef\].

[lr]{}\
\
\
Leading lepton $\pt$ & $\pt  > 20\GeV$\
Sub-leading lepton $\pt$ & $\pt  > 10\GeV$\
Additional electrons (muons) $\pt$ & $\pt  > 7~(5)\GeV$\
Pseudorapidity of electrons (muons) & $|\eta| < 2.5~(2.4)$\
Sum of scalar $\pt$ of all stable particles within $\Delta R < 0.4$ from lepton & $< 0.4 \pt$\
\
\
\
Inv. mass of the $\PZ_1$ candidate & $40 < m(\PZ_{1})< 120\GeV$\
Inv. mass of the $\PZ_2$ candidate & $12 < m(\PZ_{2})< 120\GeV$\
Distance between selected four leptons & $\Delta R(\ell_{i}\ell_{j})>0.02$\
Inv. mass of any opposite-sign lepton pair & $m(\ell^{+}_{i}\ell^{-}_{j})>4\GeV$\
Inv. mass of the selected four leptons & $105 < m_{4\ell} < 140\GeV$\

It has been verified in simulation that the reconstruction efficiency for events originating from the fiducial phase space defined in this way only weakly depends on the Higgs boson properties and production mechanism. The systematic effect associated with the 