Constraints on spin-0 dark matter mediators and invisible Higgs decays using ATLAS 13 TeV pp collision data with two top quarks and missing transverse momentum in the final state
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2023-06-13
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The European Physical Journal C
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Springer Berlin Heidelberg
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Abstract
This paper presents a statistical combination of
searches targeting final states with two top quarks and invis-
ible particles, characterised by the presence of zero, one or
two leptons, at least one jet originating from a b-quark and
missing transverse momentum. The analyses are searches for
phenomena beyond the Standard Model consistent with the
direct production of dark matter in pp collisions at the LHC,
using 139 fb−1 of data collected with the ATLAS detec-
tor at a centre-of-mass energy of 13 TeV. The results are
interpreted in terms of simplified dark matter models with
a spin-0 scalar or pseudoscalar mediator particle. In addi-
tion, the results are interpreted in terms of upper limits on
the Higgs boson invisible branching ratio, where the Higgs
boson is produced according to the Standard Model in associ-
ation with a pair of top quarks. For scalar (pseudoscalar) dark
matter models, with all couplings set to unity, the statistical
combination extends the mass range excluded by the best of
the individual channels by 50 (25) GeV, excluding mediator
masses up to 370 GeV. In addition, the statistical combina-
tion improves the expected coupling exclusion reach by 14%
(24%), assuming a scalar (pseudoscalar) mediator mass of
10 GeV. An upper limit on the Higgs boson invisible branch-
ing ratio of 0.38 (0.30+0.13
−0.09 ) is observed (expected) at 95%
confidence level.
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The European Physical Journal C. 2023 Jun 13;83(6):503