A search for high-mass resonances decaying to $\tau^{+}\tau^{-}$ in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector

TL;DR

This paper reports a search for high-mass $Z'$ resonances decaying into tau pairs in proton-proton collisions at 8 TeV, setting limits on their production and excluding certain mass ranges based on ATLAS data.

Contribution

It provides the first limits on $Z'$ bosons decaying to tau pairs at 8 TeV, including models with enhanced third-generation fermion couplings.

Findings

No significant excess observed above Standard Model expectations.

Excluded $Z'$ masses below 2.02 TeV at 95% credibility.

Set limits on $Z'$ models with enhanced third-generation couplings.

Abstract

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.