2006/08/31 by John Boersma
Physics and Astronomy · #Anomaly (physics) #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Decoupling (probability) #Gauge (firearms) #Gauge boson #Gauge theory #Higgs boson #Lepton #Limit (mathematics) #Nuclear physics #Parameter space #Particle physics #Particle physics theoretical and experimental studies #Physics #Physics beyond the Standard Model #Quantum mechanics #Resonance (particle physics) #Standard Model (mathematical formulation) #Statistics #hep-ph
paper · pdf · doi:10.1103/physrevd.74.115008
published as Phys.Rev.D74:115008,2006 · Conforms to published version. Minor clarifications and corrections, and additions to acknowledgments
openalex publication_date 2006/12/14 · arxiv created 2006/12/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Recent direct searches for new massive particles place constraints on the free parameters of the littlest Higgs model. Depending on the choice of model free parameters, the direct-search limit on the global symmetry-breaking scale f can range from as low as a few hundred GeV to in excess of 4.5 TeV. The most stringent constraints are from exclusion of the AH using high-mass dilepton resonance searches. The ZH provides the best constraint in parameter regions where the AH decouples from leptons. Current top pair resonance data approach but do not yet reach a useful limit in the anomaly-cancelling case, but do provide a constraint for a limited range of parameters in other cases. A neutral gauge boson is shown to be undetectable in dilepton resonances for a significant range of parameter space due to decoupling from standard model leptons, providing a counterexample to broad claims that a new neutral gauge boson (sometimes generically referred to as a Z^\ensuremath') is ruled out to a high-mass scale.