Search for low-mass vector and scalar resonances decaying into a quark-antiquark pair in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This paper reports a search for low-mass quark-antiquark resonances in proton-proton collisions at 13 TeV, using advanced jet substructure techniques to set new limits on possible new particles in the 50-250 GeV range.

Contribution

It introduces a novel search strategy employing the ParticleNet algorithm and large-radius jet analysis to improve sensitivity for low-mass resonance detection.

Findings

No evidence for new resonances was observed.

Set the most stringent limits to date on scalar and vector resonance couplings in 50-250 GeV range.

Analyzed 13 fb$^{-1}$ of data from the CMS experiment.

Abstract

A search for resonances with masses from 50 to 300 GeV decaying into a quark-antiquark pair is presented. The search uses proton-proton collision data at $\sqrt{s}$ = 13 TeV collected by the CMS experiment at the CERN LHC in 2016$-$2018, corresponding to an integrated luminosity of 13 fb$^{-1}$. Two coupling scenarios are considered, with the resonances coupled either equally to all flavors of quarks or preferentially to bottom quarks. The search targets resonances produced in association with hard initial-state radiation, resulting in a large-radius jet with a two-pronged substructure. The ParticleNet algorithm is used to distinguish resonance decays to bottom quark pairs from lighter quark pairs and to suppress background processes. The invariant jet mass spectrum is scrutinized for peaking excesses over a falling background. No evidence for such resonances is observed. Limits are set on the couplings of new scalar and vector resonances to quarks, representing the most stringent limits to date in the mass range of 50$-$250 GeV.