Search for dark matter produced in association with a dark Higgs boson decaying into a bottom quark-antiquark pair in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This paper reports a search for dark matter produced alongside a dark Higgs boson decaying into bottom quarks, using 13 TeV proton-proton collision data from the CMS detector, setting new limits on model parameters.

Contribution

It presents the most stringent experimental limits to date on dark Higgs boson masses and mediator masses in a specific dark matter production model.

Findings

Excluded mediator masses up to 4.5 TeV for a 50 GeV dark Higgs boson.

Excluded mediator masses up to 2.5 TeV for a 150 GeV dark Higgs boson.

Set 95% confidence level upper limits on the signal strength for dark Higgs masses below 160 GeV.

Abstract

A search for dark matter produced in association with a dark Higgs boson decaying into a bottom quark-antiquark pair has been performed using proton-proton collision data at a center-of-mass energy of 13 TeV. The search uses data collected with the CMS detector at the CERN LHC during the 2016$-$2018 data-taking period, corresponding to an integrated luminosity of 138 fb$^{-1}$. The results are interpreted in terms of a theoretical model of dark matter production that, together with a spin-1 gauge boson mediator, predicts the existence of a Higgs-boson-like particle in the dark sector (i.e., a dark Higgs boson). This search focuses on an experimental signature with large missing transverse momentum from dark matter production and a resonant structure in the invariant mass of the bottom quark-antiquark pair from the dark Higgs boson decay. Upper limits at 95% confidence level on the signal strength for dark Higgs boson mass hypotheses below 160 GeV are set. Values of the mediator mass up to 4.5 (2.5) TeV are excluded at 95% confidence level for a dark Higgs boson mass of 50 (150) GeV. This represents the most stringent limits set to date for the dark Higgs boson masses considered in this study.