1999/06/11 by Heather E. Logan, Logan, Heather E.
Physics and Astronomy · #Black Holes and Theoretical Physics #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.48550/arxiv.hep-ph/9906332
151 pages, 17 Postscript figures
arxiv created 1999/06/11 · openalex publication_date 1999/06/11 · arxiv updated 2009/11/30 · openalex created_date 2024/04/11 · openalex updated_date 2026/07/28
We explore the radiative corrections to the process Z --> b b-bar in models with extended Higgs sectors. The observables Rb (the Z hadronic branching fraction to b b-bar) and the b-quark asymmetry Ab = (gL2 - gR2)/(gL2 + gR2) are sensitive to these corrections. We find that in models containing only Higgs doublets, singlets, or larger multiplets constrained by a custodial SU(2) symmetry, the radiative corrections to Rb involving charged Higgs bosons always worsen the Standard Model fit to electroweak data. Thus, the present Rb data can be used to set lower bounds on the charged Higgs masses in such models. Radiative corrections to Rb involving light neutral Higgs bosons in models with enhanced couplings to b b-bar can improve the Standard Model fit to present data. The Higgs sector alone cannot explain a significant deviation of Ab from its Standard Model prediction. We present general formulas for the corrections to Rb and Ab in an SU(2)xU(1) electroweak model with an arbitrary extended Higgs sector, and derive explicit results for a number of specific models.