DOI: 10.17182/hepdata.80152.v1/t6
title: "Table 6" of "Measurements of the pp$\to$ZZ production cross section and the Z$\to 4\ell$ branching fraction, and constraints on anomalous triple gauge couplings at $\sqrt{s} =$ 13 TeV"

description: The measured Z BR to 4l. The first systematic uncertainty is the combined systematic uncertainty excluding luminosity and theortical sources, the second is theoretical uncertianty on the extrapolation from the selected region to the total phase space, the third is the luminosity uncertianty
description: CERN-LHC. Measurements of the cross section for ZZ and Z production using the 4l decay channels in proton-proton collisions at a centre-of-mass energy of 13 TeV with 35.9 fb^-1 of data collected in 2016. The final states used are 4 electrons, 4 muons, and 2 electrons and 2 muons.

Selection for all regions:
- 4e, 4mu or 2e2mu
- Ambiguities in pairing are resolved by choosing the combination that results in the smallest value of the sum |mll - mZ| for one of the two pairs, where mll is the mass of the dilepton system and mZ = 91.2 GeV.
- ptLepton &gt; 7 (5) GeV (at least one with ptLepton &gt; 20 and a second with ptLepton &gt; 12 (10) GeV for electrons (muons))
- |etaLepton| &lt; 2.5 (2.4) for electrons (muons)
- At least one lepton pair is required to have invariant mass between 40 and 120 GeV and the second pairing less than 120. 
- All oppositely charged paris must have m_ll &gt; 4 GeV
- min(DeltaR(l,l)) &gt; 0.02 and electrons from muons by min(DeltaR(l,l)) &gt; 0.05.
- If multiple 4l candidates within an event pass all selections, first the one with mZ1 closest to the nominal Z boson mass is chosen. In the rare case of further ambiguity, which may arise in less than 0.5% of events when five or more passing lepton candidates are found, the Z2 candidate that maximizes the scalar pT sum of the four leptons is chosen.
- The distance of clossest approach between each lepton candidate and the event vertex is required ot be less than 0.5 cm and the 3D impact paramter significance is required to be less than 10
- Riso defined as the sum of charged hadron, neutral hadron, photon pT minus pile up contributions over pTLepton is requred to be less than 0.35
- Missing transverse momentum pTmiss is required to be less than 25 GeV
- The transverse mass calculated with any lepton candidate and pTmiss is required to be less than 30 GeV


The ZZ selection is further defined by:
- m4l is required ot have invariant mass between 80 and 100 GeV 

The Z selection is further defined by:
- At least one lepton pair is required to have invariant mass between 40 and 120 GeV and the second pairing less than 120. 
- m4l is required ot have invariant mass between 80 and 100 GeV 

The aTGC selection is further defined by:
- m4l is required ot have invariant mass greater than 100 GeV


The ZZ fiducial region is further defined by:
- ptLepton &gt; 5 GeV with at least one with ptLepton &gt; 20 and a second with ptLepton &gt; 10 GeV f
- |etaLepton| &lt; 2.5
- All oppositely charged paris must have m_ll &gt; 4 GeV
- Both mll pairings are required to have invariant mass between 60 and 120 GeV

The Z fiducial region is further defined by:
- ptLepton &gt; 5 GeV with at least one with ptLepton &gt; 20 and a second with ptLepton &gt; 10 GeV f
- |etaLepton| &lt; 2.5
- All oppositely charged paris must have m_ll &gt; 4 GeV
- At least one lepton pair is required to have invariant mass between greater than 40 GeV
- m4l is required ot have invariant mass between 80 and 100 GeV