DOI: 10.17182/hepdata.65388.v1/t7
title: "Table 7" of "Search for high-mass dilepton resonances in pp collisions at sqrt(s) = 8 TeV with the ATLAS detector"

description: Expected and observed limits at 95% CL on the strength of the Z' boson coupling relative to that of the SM Z boson (gamma') for the combined dielectron and dimuon channels as a function of the mixing between the generators of the (B-L) and the weak hypercharge Y gauge groups (theta_Min) in the Minimal Z' Models parameterization. The limits are set for several representative values of the mass of the Z' boson, M_Z' Minimal.
description: CERN-LHC. Search for high-mass resonances decaying to dielectron or dimuon final states in proton-proton collisions at a center-of-mass energy of 8 TeV with 20.3 fb-1 in the dimuon channel and 20.5 fb-1 in the dielectron channel, collected in 2012. The final states used are 2 electrons or 2 muons.

All events meet the following requirements:

- At least one reconstructed primary vertex with at least associated 3 tracks having pT &gt; 0.4 GeV.
- For data, events occurred during periods of stable beam with all relevant detector sub-systems operational.

Events are triggered by one of the following trigger selections:
- A trigger requiring the presence of at least 2 energy deposits in the electromagnetic calorimeter, one with pT &gt; 35 GeV, and the other with pT &gt; 25 GeV. The shower profiles are required to be consistent with those expected for electromagnetic shower.
- A trigger requiring the presence of at least one isolated muon with pT &gt; 24 GeV or at least one muon with pT &gt; 36 GeV.

The 2 electron channel is defined as:
- 2 electrons with ET &gt; 30 GeV.
- 1 "leading" electron with ET &gt; 40 GeV.
- Electrons are in pseudorapidity range &lt; 2.5.
- Electrons in pseudorapidity range [1.37,1.52] are excluded.
- Electron track and cluster satisfy criteria requiring shower profiles consistent with those expected.
- Minimum requirement on the amount of transition radiation for electron tracks.
- At least one hit in the first layer of the pixel detector required if an active pixel layer is traversed.
- Electrons are isolated within a cone of radius DeltaR = 0.2 in the (eta,phi) plane: for leading electron energy in the cone &lt; 0.007 * ET + 5.0 GeV, for subleading electron &lt; 0.022 * ET + 6.0 GeV.

The 2 muon channel is defined as:
- 2 oppositely-charged muons with pT &gt; 25 GeV, each with a track component in both the Muon Spectrometer and the Inner Detector.
- Each muon has a minimum number of hits in each ID component.
- Impact parameter along the beam axis is &lt; 1 mm, and transverse impact parameter is &lt; 0.2 mm.
- At least one muon in the pair passes a "tight" selection consisting of:
&gt;=1 hit in both trigger chamber layers;
&gt;=3 hits in each of three stations of the MS, or, for muons in the very forward region, &gt;=2 hits in the CSC and &gt;=3 hits in the middle and outer MS stations;
Difference between ID and MS track momentum measurements is &lt; 5 sigma.
- One muon in the pair is allowed to pass a modified selection, consisting of:
Muon is within pseudorapidity range &lt; 1.05;
&gt;=5 precision hits in each of the inner and outer stations of the MS;
&gt;=1 hit in one trigger chamber layer;
Difference between ID and MS track momentum measurements is &lt; 5 sigma.

In all cases, the pair candidate with the highest sum pT is selected.