Search for narrow resonances in the b-tagged dijet mass spectrum in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This study searches for narrow resonances decaying into b-tagged dijets in 13 TeV proton-proton collisions, setting new limits on certain new particle models with no evidence of discovery.

Contribution

It provides the most stringent limits to date on excited b quarks and Z' bosons decaying to b-containing dijets using advanced b-tagging techniques.

Findings

No evidence for new resonances was observed.

Upper limits were set on production cross sections for various models.

Excluded Z' bosons with masses 1.8-2.4 TeV and excited b quarks 1.8-4.0 TeV.

Abstract

A search is performed for narrow resonances decaying to final states of two jets, with at least one jet originating from a b quark, in proton-proton collisions at $\sqrt{s}$ = 13 TeV. The data set corresponds to an integrated luminosity of 138 fb$^{-1}$ collected with the CMS detector at the LHC. Jets originating from energetic b hadrons are identified through a b-tagging algorithm that utilizes a deep neural network or the presence of a muon inside a jet. The invariant mass spectrum of jet pairs is well described by a smooth parametrization and no evidence for the production of new particles is observed. Upper limits on the production cross section are set for excited b quarks and other resonances decaying to dijet final states containing b quarks. These limits exclude at 95% confidence level models of Z' bosons with masses from 1.8 to 2.4 TeV and of excited b quarks with masses from 1.8 to 4.0 TeV. This is the most stringent exclusion of excited b quarks to date.