Search for dark matter produced in association with a Higgs boson decaying to a pair of bottom quarks in proton–proton collisions at $$\sqrt{s}=13\,\text {Te}\text {V} $$ s = 13 Te

Abstract

A search for dark matter produced in association with a Higgs boson decaying to a pair of bottom quarks is performed in proton–proton collisions at a center-of-mass energy of 13 collected with the CMS detector at the LHC. The analyzed data sample corresponds to an integrated luminosity of 35.9 . The signal is characterized by a large missing transverse momentum recoiling against a bottom quark–antiquark system that has a large Lorentz boost. The number of events observed in the data is consistent with the standard model background prediction. Results are interpreted in terms of limits both on parameters of the type-2 two-Higgs doublet model extended by an additional light pseudoscalar boson (2HDM+ ) and on parameters of a baryonic simplified model. The 2HDM+ model is tested experimentally for the first time. For the baryonic model, the presented results constitute the most stringent constraints to date.

Search for dark matter particles produced in association with a Higgs boson in proton-proton collisions at $$ \sqrt{\mathrm{s}} $$ = 13 TeV

“…A detailed description of the simulated samples used for the h → bb, h → γγ, and h → ττ analyses can be found in refs. [30][31][32]. The production of a Higgs boson in association with a Z boson decaying to a pair of neutrinos is an irreducible background for all the final states considered.…”

“…For the AK8 jets, subjets inside the jet are required to be tagged as b jets using the CSVv2 algorithm. A likelihood for the CA15 jet to contain two b quarks is derived by combining the information from the primary and secondary vertices and tracks in a multivariate discriminant optimized to distinguish CA15 jets originating from the h → bb decay from those produced by energetic light-flavor quarks or gluons [31].…”

“…In this section we briefly discuss the analysis strategies in the previously published [30][31][32] h → bb, h → γγ, and h → ττ, channels, and provide full descriptions of the new analyses in the h → WW and h → ZZ decay channels. The summary of all the decay channels contributing to the combination is presented in table 1.…”

“…To select the h → bb candidates using the AK8 jet, one or both subjets are required to pass the loose b tagging criteria, which has an efficiency of 85%, and a misidentification rate of about 10% for jets originating from light-flavor quarks or gluons. In the case of the CA15 jets, a multivariate double b tagging algorithm [82] is used to discriminate the signal from the background of light-flavor jets [31], with an efficiency of 50% and a misidentification rate of 10%. The AK8 (CA15) analysis requires the Higgs boson candidate mass to be in the 105-135 (100-150) GeV range to reduce nonresonant backgrounds.…”

“…In this paper, we describe the first search for mono-Higgs production in the W + W − and ZZ Higgs boson decay channels, as well as the combination of these searches with the previously published results in the bb [30,31], γγ [32], and τ + τ − [32] channels. (Hereafter, for simplicity we refer to bb, τ + τ − and W + W − as bb, ττ and WW, respectively.)…”