Search for dark matter in association with a Higgs boson decaying to $b$-quarks in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

TL;DR

This paper reports a search for dark matter produced alongside a Higgs boson decaying to bottom quarks in proton-proton collisions at 13 TeV, using ATLAS data, with results consistent with background expectations.

Contribution

It introduces a novel search strategy for dark matter in association with a Higgs boson decaying to bottom quarks at the LHC, interpreting results within specific theoretical models.

Findings

No significant excess observed over background

Constraints placed on simplified dark matter models

Method demonstrated for Higgs decay to bottom quarks in dark matter searches

Abstract

A search for dark matter pair production in association with a Higgs boson decaying to a pair of bottom quarks is presented, using 3.2 $fb^{-1}$ of $pp$ collisions at a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the LHC. The decay of the Higgs boson is reconstructed as a high-momentum $b\bar{b}$ system with either a pair of small-radius jets, or a single large-radius jet with substructure. The observed data are found to be consistent with the expected backgrounds. Results are interpreted using a simplified model with a $Z'$ gauge boson mediating the interaction between dark matter and the Standard Model as well as a two-Higgs-doublet model containing an additional $Z'$ boson which decays to a Standard Model Higgs boson and a new pseudoscalar Higgs boson, the latter decaying into a pair of dark matter particles.