Search for dark photons in decays of Higgs bosons produced in association with Z bosons in proton-proton collisions at $\sqrt{s}=$ 13 TeV

Abstract

A search is presented for a Higgs boson that is produced in association with a Z boson and that decays to an undetected particle together with an isolated photon. The search is performed by the CMS Collaboration at the Large Hadron Collider using a data set corresponding to an integrated luminosity of 137 fb${}^{-1}$ recorded at a center-of-mass energy of 13 TeV. No significant excess of events above the expectation from the standard model background is found. The results are interpreted in the context of a theoretical model in which the undetected particle is a massless dark photon. An upper limit is set on the product of the cross section for associated Higgs and Z boson production and the branching fraction for such a Higgs boson decay, as a function of the Higgs boson mass. For a mass of 125 GeV, assuming the standard model production cross section, this corresponds to an observed (expected) upper limit on this branching fraction of 4.6 (3.6)% at 95% confidence level. These are the first limits on Higgs boson decays to final states that include an undetected massless dark photon.

Replaced with the published version. Added the journal reference and the DOI. All the figures and tables, including additional supplementary figures and tables, can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/EXO-19-007 (CMS Public Pages)

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Cited by in corpus (12)

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• Search for light long-lived neutral particles produced in $pp$ collisions at $\sqrt{s}=$ 13 TeV and decaying into collimated leptons or light hadrons with the ATLAS detector
• Observation of electroweak production of two jets in association with an isolated photon and missing transverse momentum, and search for a Higgs boson decaying into invisible particles at 13 TeV with the ATLAS detector
• Search for dark photons in Higgs boson production via vector boson fusion in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• The 7% Rule: A Maximum Entropy Prediction on New Decays of the Higgs Boson
• Unitarity Constraints and Collider Searches for Dark Photons
• Is the decay of the Higgs boson to a photon and a dark photon currently observable at the LHC?
• Observability of the Higgs boson decay to a photon and a dark photon
• String (gravi)photons, "dark brane photons", holography and the hypercharge portal
• Semi-dark Higgs decays: sweeping the Higgs neutrino floor
• Modification of T/E models and their multi-field versions