One-Loop Corrections to the S and T Parameters in a Three Site Higgsless Model

dc.creatorMatsuzaki, Shinya
dc.creatorChivukula, R. Sekhar
dc.creatorSimmons, Elizabeth H.
dc.creatorTanabashi, Masaharu
dc.date2006-07-17
dc.date2007-02-27
dc.date.accessioned2026-07-07T10:25:09Z
dc.date.available2026-07-07T10:25:09Z
dc.descriptionIn this paper we compute the the one-loop chiral logarithmic corrections to the S and T parameters in a highly deconstructed Higgsless model with only three sites. In addition to the electroweak gauge bosons, this model contains a single extra triplet of vector states (which we denote ρ^{\pm} and ρ^0), rather than an infinite tower of "KK" modes. We compute the corrections to S and T in 'tHooft-Feynman gauge, including the ghost, unphysical Goldstone-boson, and appropriate "pinch" contributions required to obtain gauge-invariant results for the one-loop self-energy functions. We demonstrate that the chiral-logarithmic corrections naturally separate into two parts, a model-independent part arising from scaling below the ρmass, which has the same form as the large Higgs-mass dependence of the S or T parameter in the standard model, and a second model-dependent contribution arising from scaling between the ρmass and the cutoff of the model. The form of the universal part of the one-loop result allows us to correctly interpret the phenomenologically derived limits on the S and T parameters (which depend on a "reference" Higgs-boson mass) in this three-site Higgsless model. Higgsless models may be viewed as dual to models of dynamical symmetry breaking akin to "walking technicolor", and in these terms our calculation is the first to compute the subleading 1/N corrections to the S and T parameters. We also discuss the reduction of the model to the ``two-site'' model, which is the usual electroweak chiral lagrangian, noting the ``non-decoupling'' contributions present in the limit as M_ρgoes to infinity.
dc.description58 pages; uses JHEP and axodraw. Extensively corrected to incorporate consistent perturbative expansion, additional pinch contributions, and running of delocalization parameter. Footnotes added
dc.identifierhttps://arxiv.org/abs/hep-ph/0607191
dc.identifierhttp://arxiv.org/abs/hep-ph/0607191
dc.identifierPhys.Rev.D75:073002,2007
dc.identifierdoi:10.1103/PhysRevD.75.073002
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/176442
dc.subjectHigh Energy Physics - Phenomenology
dc.titleOne-Loop Corrections to the S and T Parameters in a Three Site Higgsless Model
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