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

TL;DR

This paper reports a search for low mass vector resonances decaying into quark-antiquark pairs in proton-proton collisions at 13 TeV, using CMS data from 2016 and 2017, with no evidence found but setting new limits.

Contribution

It introduces a novel search extending the mass range up to 450 GeV using jet substructure techniques, combining data from 2016 and 2017 for improved sensitivity.

Findings

No evidence of narrow vector resonances was observed.

Set the most sensitive limits to date for masses between 50 and 300 GeV.

Extended the search to 300-450 GeV for the first time with jet substructure.

Abstract

A search for low mass narrow vector resonances decaying into quark-antiquark pairs is presented. The analysis is based on data collected in 2017 with the CMS detector at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 41.1 fb$^{-1}$. The results of this analysis are combined with those of an earlier analysis based on data collected at the same collision energy in 2016, corresponding to 35.9 fb$^{-1}$. Signal candidates will be recoiling against initial state radiation and are identified as energetic, large-radius jets with two pronged substructure. The invariant jet mass spectrum is probed for a potential narrow peaking signal over a smoothly falling background. No evidence for such resonances is observed within the mass range of 50-450 GeV. Upper limits at the 95% confidence level are set on the coupling of narrow resonances to quarks, as a function of the resonance mass. For masses between 50 and 300 GeV these are the most sensitive limits to date. This analysis extends the earlier search to a mass range of 300-450 GeV, which is probed for the first time with jet substructure techniques.