Model-independent search for pair production of new bosons decaying into muons in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This paper reports a comprehensive, model-independent search for new bosons decaying into four muons in proton-proton collisions at 13 TeV, setting upper limits and excluding large parameter regions across multiple theoretical models.

Contribution

It presents the first combined, model-independent analysis of pair-produced bosons decaying into muons, including displaced signatures, and extends exclusion limits in various new physics models.

Findings

No significant excess observed over background.

Set upper limits on production cross section times branching ratio.

Excluded large parameter regions in multiple new physics models.

Abstract

The results of a model-independent search for the pair production of new bosons within a mass range of 0.21 $\lt$ $m$ $\lt$ 60 GeV, are presented. This study utilizes events with a four-muon final state. We use two data sets, comprising 41.5 fb$^{-1}$ and 59.7 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV, recorded in 2017 and 2018 by the CMS experiment at the CERN LHC. The study of the 2018 data set includes a search for displaced signatures of a new boson within the proper decay length range of 0 $\lt$ $c\tau$ $\lt$ 100 $\mu$m. Our results are combined with a previous CMS result, based on 35.9 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV collected in 2016. No significant deviation from the expected background is observed. Results are presented in terms of a model-independent upper limit on the product of cross section, branching fraction, and acceptance. The findings are interpreted across various benchmark models, such as an axion-like particle model, a vector portal model, the next-to-minimal supersymmetric standard model, and a dark supersymmetric scenario, including those predicting a non-negligible proper decay length of the new boson. In all considered scenarios, substantial portions of the parameter space are excluded, expanding upon prior results.