CMS-PAS-EXO-25-001

CMS-PAS-EXO-25-001
Search for Higgs compositeness effects in high-mass dilepton final states in proton-proton collisions at $ \sqrt{s} = $ 13 and 13.6 TeV
CMS Collaboration
2026-07-06

Abstract: A search for beyond the standard model effects in high-energy dielectron and dimuon final states with the CMS detector is performed, with a specific focus on Higgs compositeness. The search uses data collected at LHC at 13 and 13.6 TeV center-of-mass energies, for a total integrated luminosity of 207 fb$ ^{-1} $. These compositeness effects imply the presence of new massive boson resonances with couplings to difermions and dibosons. The analysis uses a reweighting procedure that is exact at next-to-leading order in QCD. Assuming new boson states with mass well above the TeV scale, an effective field theory approach provides stringent bounds on the oblique parameters $ {\cal W} $ and $ {\cal Y} $, which are zero in the standard model. One-dimensional fits, where only one of the oblique parameters is allowed to deviate from zero, provide the following limits: $ -3.9 \times 10^{-4} < {\cal Y} < 3.5 \times 10^{-4} $ and $ -2.1 \times 10^{-4} < {\cal W} < 1.6 \times 10^{-4} $ at 95% confidence level. More stringent compositeness constraints are derived under the assumption that a new Z$ ^\prime $ resonance is physically present inside or slightly above the visible mass spectrum. Various theoretical scenarios are considered in this context, including cases with large resonance decay width.
Links: CDS record (PDF) ; CADI line (restricted) ;

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