DOI: 10.17182/hepdata.68362.v1/t8
title: "Table 8" of "A search for high-mass resonances decaying to $\tau^{+}\tau^{-}$ in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector"

description: Observed 95% CL upper limits on the cross-section times branching fraction to tau+tau- for Z'L and Z'R production for the combination of the had-had and lep-had channels.
description: CERN-LHC. A search for high-mass resonances decaying into $\tau^{+}\tau^{-}$ final states using proton-proton collisions at $\sqrt{s}= 8$ TeV produced by the Large Hadron Collider is presented. The data were recorded with the ATLAS detector and correspond to an integrated luminosity of 19.5-20.3 fb$^{-1}$. No statistically significant excess above the Standard Model expectation is observed; 95% credibility upper limits are set on the cross section times branching fraction of $Z^{\prime}$ resonances decaying into $\tau^+\tau^-$ pairs as a function of the resonance mass. As a result, $Z^{\prime}$ bosons of the Sequential Standard Model with masses less than 2.02 TeV are excluded at 95% credibility. The impact of the fermionic couplings on the $Z^{\prime}$ acceptance is investigated and limits are also placed on a $Z^{\prime}$ model that exhibits enhanced couplings to third-generation fermions

All events meet the following requirements:
- At least one reconstructed primary vertex with at least 3 associated 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 one energy deposit in the calorimeter with pT &gt; 125 GeV that has 1-3 associated tracks and passes strict hadronic tau identification criteria based on tracking and calorimetric information (had-had channel).
- A trigger requiring the presence of at least one energy deposit in the electromagnetic calorimeter either with pT &gt; 24 GeV and tight isolation or with pT &gt; 60 GeV without isolation. The shower profiles are required to be consistent with those expected for electromagnetic showers (lep-had).
- 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 (lep-had).

The had-had channel is defined as:
- No electrons with pT &gt; 15 GeV in the pseudorapidity range [0,1.37] or [1.52,2.47]
- No muons with pT &gt; 10 GeV in the pseudorapidity range [0,2.5]
- At least 2 hadronic tau decays with visible pT &gt; 50 GeV 
- The "leading" hadronic tau decay has visible pT &gt; 150 GeV
- Hadronic tau decays are in the pseudorapidity range [0,1.37] or [1.52,2.47]
- Leading 2 hadronic tau decays pass tau identification
- Leading 2 hadronic tau decays have opposite electric charge sign
- Angle between the leading 2 hadronic tau decays in the transverse plane &gt; 2.7 radians
- Total transverse mass of leading two hadronic tau decays and missing transverse momentum is above a threshold defined for each Z' mass hypothesis

The lep-had channel is defined as: 
- 1 isolated muon OR 1 isolated electron; pT &gt; 30 GeV 
- Electrons are in the pseudorapidity range [0,1.37] or [1.52,2.47]
- Electron track and cluster satisfy criteria requiring shower profiles consistent with those expected
- Electrons are considered isolated if the summed pT of tracks in dR&lt;0.3 is less than 5% of the electron pT and the summed energy in dR&lt;0.2 is less than (5 GeV + 0.7% of the electron pT)
- Muons are in the pseudorapidity range [0,2.5]
- Muons are considered isolated if the summed pT of tracks in dR&lt;0.3 is less than 5% of the muon pT
- No additional electrons with pT &gt; 15 GeV
- No additional muons with pT &gt; 10 GeV
- At least 1 hadronic tau decay with visible pT &gt; 30 GeV
- Hadronic tau decays are in the pseudorapidity range [0,1.37] or [1.52,2.47]
- Leading hadronic tau decay passes tau identification
- Isolated lepton and leading hadronic tau decay have opposite electric charge sign
- Angle between isolated lepton and leading hadronic tau decay in the transverse plane &gt; 2.7 radians
- Total transverse mass of isolated lepton, leading hadronic tau decay and missing transverse momentum is above a threshold defined for each Z' mass hypothesis

The transverse mass is defined as:
\begin{equation*} 
m_{\rm T}(p^{A},p^{B})=\sqrt{2p_{\rm T}^{A}p_{\rm T}^{B} \left ( 1-\cos\Delta\phi(p^{A},p^{B}) \right )} \, , 
\end{equation*}
where $p^{A}$ and $p^{B}$ are two reconstructed physics objects with transverse momenta $p_{\rm T}^{A}$ and $p_{\rm T}^{B}$, respectively, which subtend an angle of $\Delta\phi(p^{A},p^{B})$ in the transverse plane.

The total transverse mass is defined as:
\begin{equation*}
m_{\rm T}^{\rm tot}(\tau_1,\tau_2,E_{\rm T}^{\rm miss}) = \sqrt{m_{\rm T}^2(\tau_1,\tau_2) + m_{\rm T}^2(\tau_1,E_{\rm T}^{\rm miss}) + m_{\rm T}^2(\tau_2,E_{\rm T}^{\rm miss})}\, , 
\end{equation*}
where $\tau_1$ and $\tau_2$ denote the reconstructed visible decay products of the two tau leptons ($e$, $\mu$ or $\tau_{\rm had-vis}$).