2025/11/12 by S. Dawson, Arnab Roy, Dawson, Sally +3 · 1 citation
Physics and Astronomy · #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2511.09778
openalex publication_date 2025/11/12 · openalex created_date 2025/11/15 · openalex updated_date 2026/07/28
We discuss the HL-LHC sensitivity to probe new invisible particles including scalars and fermions using semi-visible Higgs decays in the pp→ ZH, Z→ jj (ℓ+ℓ-), ~H→ ℓ+ℓ- (jj) + ~\rm E /T production mode. The kinematics of these decays allow new particle masses below m\lesssim 50 GeV. We carry out our analysis using both a cut-based approach and a multivariate method based on a boosted decision tree. We work within the dark-SMEFT framework with operators up to dimension six and a discrete ℤ2 symmetry under which the new particles are odd and the SM particles are even. We compare our results to those obtained from considering the invisible Z-width, as well as perturbative unitarity arguments. Finally, we outline kinematic strategies at the LHC to distinguish different operator structures of the postulated invisible particles.