A search for long-lived particles (LLPs) decaying in the CMS muon detectors is presented. A data sample of proton-proton collisions at corresponding to an integrated luminosity of , recorded at the LHC in 2016–2018, is used. The decays of LLPs are reconstructed as high multiplicity clusters of hits in the muon detectors. In the context of twin Higgs models, the search is sensitive to LLP masses from 0.4 to 55 GeV and a broad range of LLP decay modes, including decays to hadrons, leptons, electrons, or photons. No excess of events above the standard model background is observed. The most stringent limits to date from LHC data are set on the branching fraction of the Higgs boson decay to a pair of LLPs with masses below 10 GeV. This search also provides the best limits for various intervals of LLP proper decay length and mass. Finally, this search sets the first limits at the LHC on a dark quantum chromodynamic sector whose particles couple to the Higgs boson through gluon, Higgs boson, photon, vector, and dark-photon portals, and is sensitive to branching fractions of the Higgs boson to dark quarks as low as . © 2024 CERN, for the CMS Collaboration2024CERN 
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                            Illuminating all-hadronic final states with a photon: Exotic decays of the Higgs boson to four bottom quarks in vector boson fusion plus gamma at hadron colliders
                        
                    
    
            We investigate the potential to detect Higgs boson decays to four bottom quarks through a pair of pseudoscalars, a final state that is predicted by many theories beyond the Standard Model. For the first time, the signal sensitivity is evaluated for the final state using the vector boson fusion (VBF) production with and without an associated photon, for the Higgs at , at hadron colliders. The signal significance is to , depending on the pseudoscalar mass , when setting the Higgs decay branching ratio to unity, using an integrated luminosity of at . This corresponds to an upper limit of 0.3, on the Higgs branching ratio to four bottom quarks, with a nonobservation of the decay. We also consider several variations of selection requirements—input variables for the VBF tagging and the kinematic variables for the photon—that could help guide the design of new triggers for the Run-3 period of the LHC and for the HL-LHC. Published by the American Physical Society2024 
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                            - Award ID(s):
- 2209370
- PAR ID:
- 10517422
- Publisher / Repository:
- APS
- Date Published:
- Journal Name:
- Physical Review D
- Volume:
- 109
- Issue:
- 11
- ISSN:
- 2470-0010
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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