A search for pair-produced resonances in four-jet final states at $\sqrt{s}$ =13 TeV with the ATLAS detector

TL;DR

This paper reports a search for pair-produced massive coloured resonances decaying into four jets using 13 TeV proton-proton collision data from ATLAS, setting new exclusion limits on top squark and colour-octet resonance masses.

Contribution

It provides the first limits on pair-produced coloured resonances decaying into four jets at 13 TeV, including specific constraints on top squark and colour-octet resonance models.

Findings

Excluded top squark masses between 100 and 410 GeV for generic decays.

Excluded top squark masses between 100 and 470 GeV, and 480 to 610 GeV for b-quark decays.

Set limits on pair-production of massive colour-octet resonances.

Abstract

A search for massive coloured resonances which are pair-produced and decay into two jets is presented. The analysis uses 36.7 fb$^{-1}$ of $\sqrt{s}=$ 13 TeV pp collision data recorded by the ATLAS experiment at the LHC in 2015 and 2016. No significant deviation from the background prediction is observed. Results are interpreted in a SUSY simplified model where the lightest supersymmetric particle is the top squark, $\tilde{t}$, which decays promptly into two quarks through $R$-parity-violating couplings. Top squarks with masses in the range 100 GeV < $m_{\tilde{t}}$ < 410 GeV are excluded at 95% confidence level. If the decay is into a $b$-quark and a light quark, a dedicated selection requiring two $b$-tags is used to exclude masses in the ranges 100 GeV < $m_{\tilde{t}}$ < 470 GeV and 480 GeV < $m_{\tilde{t}}$ < 610 GeV. Additional limits are set on the pair-production of massive colour-octet resonances.