Search for resonances in the mass distribution of jet pairs with one or two jets identified as $b$-jets in proton--proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

TL;DR

This paper searches for high-mass resonances decaying into jet pairs with $b$-jets in proton-proton collisions at 13 TeV, setting limits on various hypothetical particles with no evidence of new phenomena found.

Contribution

It presents the first ATLAS search for resonances in the $b$-jet dijet mass spectrum at 13 TeV, excluding specific new particles within certain mass ranges.

Findings

Excluded excited $b^{*}$ quarks with masses 1.1-2.1 TeV.

Excluded leptophobic $Z'$ bosons with masses 1.1-1.5 TeV.

Set upper limits on Gaussian signal cross sections from 0.4 to 0.001 pb.

Abstract

Searches for high-mass resonances in the dijet invariant mass spectrum with one or two jets identified as $b$-jets are performed using an integrated luminosity of $3.2$ fb$^{-1}$ of proton--proton collisions with a centre-of-mass energy of $\sqrt{s}=13$ TeV recorded by the ATLAS detector at the Large Hadron Collider. No evidence of anomalous phenomena is observed in the data, which are used to exclude, at 95% credibility level, excited $b^{*}$ quarks with masses from 1.1 TeV to 2.1 TeV and leptophobic $Z'$ bosons with masses from 1.1 TeV to 1.5 TeV. Contributions of a Gaussian signal shape with effective cross sections ranging from approximately 0.4 to 0.001 pb are also excluded in the mass range 1.5-5.0 TeV.