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Title: Deconstructed Higgsless Models

Abstract

We consider the possibility of constructing realistic Higgsless models within the context of deconstructed or moose models. We show that the constraints coming from the electro-weak experimental data are very severe and that it is very difficult to reconcile them with the requirement of improving the unitarity bound of the Higgsless Standard Model. On the other hand, with some fine tuning, a solution is found by delocalizing the standard fermions along the lattice line, that is allowing the fermions to couple to the moose gauge fiel0008.

Authors:
 [1];  [2]
  1. Dipartimento di Fisica dell' Universita di Firenze, Via G. Sansone I, 50019 Sesto Fiorentino (Florence) (Italy)
  2. (Florence) (Italy)
Publication Date:
OSTI Identifier:
20787624
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 806; Journal Issue: 1; Conference: International workshop on quantum chromodynamics: Theory and experiment, Conversano, Bari (Italy), 16-20 Jun 2005; Other Information: DOI: 10.1063/1.2163752; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; FERMIONS; GAUGE INVARIANCE; HIGGS MODEL; LATTICE FIELD THEORY; MATHEMATICAL SOLUTIONS; STANDARD MODEL; UNITARITY

Citation Formats

Casalbuoni, Roberto, and Sezione INFN, Via G. Sansone I, 50019 Sesto Fiorentino. Deconstructed Higgsless Models. United States: N. p., 2006. Web. doi:10.1063/1.2163752.
Casalbuoni, Roberto, & Sezione INFN, Via G. Sansone I, 50019 Sesto Fiorentino. Deconstructed Higgsless Models. United States. doi:10.1063/1.2163752.
Casalbuoni, Roberto, and Sezione INFN, Via G. Sansone I, 50019 Sesto Fiorentino. Thu . "Deconstructed Higgsless Models". United States. doi:10.1063/1.2163752.
@article{osti_20787624,
title = {Deconstructed Higgsless Models},
author = {Casalbuoni, Roberto and Sezione INFN, Via G. Sansone I, 50019 Sesto Fiorentino},
abstractNote = {We consider the possibility of constructing realistic Higgsless models within the context of deconstructed or moose models. We show that the constraints coming from the electro-weak experimental data are very severe and that it is very difficult to reconcile them with the requirement of improving the unitarity bound of the Higgsless Standard Model. On the other hand, with some fine tuning, a solution is found by delocalizing the standard fermions along the lattice line, that is allowing the fermions to couple to the moose gauge fiel0008.},
doi = {10.1063/1.2163752},
journal = {AIP Conference Proceedings},
number = 1,
volume = 806,
place = {United States},
year = {Thu Jan 12 00:00:00 EST 2006},
month = {Thu Jan 12 00:00:00 EST 2006}
}
  • In this note we calculate the form of electroweak corrections in deconstructed Higgsless models for the case of a fermion whose weak properties arise from two adjacent SU(2) groups on the deconstructed lattice. We show that, as recently proposed in the continuum, it is possible for the value of the electroweak parameter {alpha}S to be small in such a model. In addition, by working in the deconstructed limit, we may directly evaluate the size of off-Z-pole electroweak corrections arising from the exchange of Kaluza-Klein modes; this has not been studied in the continuum. The size of these corrections is summarizedmore » by the electroweak parameter {alpha}{delta}. In one-site delocalized Higgsless models with small values of {alpha}S, we show that the amount of delocalization is bounded from above, and must be less than 25% at 95% C.L. We discuss the relation of these calculations to our previous calculations in deconstructed Higgsless models, and to models of extended technicolor. We present numerical results for a four-site model, illustrating our analytic calculations.« less
  • We study the phenomenology of a four-site Higgsless model, an extension of the minimal three-site version (BESS model), at the present operating colliders. The model predicts the existence of two neutral and four charged extra gauge bosons, Z{sub 1,2} and W{sub 1,2}{sup {+-}}. In contrast to other Higgsless models, sizeable fermion-boson couplings are still allowed by the electroweak precision data and make discovery possible in the next two years in the favoured Drell-Yan channels at the 7 TeV LHC for masses in the TeV region depending on the model parameters.
  • We identify and study the signatures of the recently proposed Higgsless models at the CERN Large Hadron Collider (LHC). We concentrate on tests of the mechanism of partial unitarity restoration in the longitudinal vector boson scattering, which is crucial to the phenomenological success of any Higgsless model and does not depend on the model-building details. We investigate the discovery reach for charged massive vector boson resonances and show that all of the preferred parameter space will be probed with 100 fb{sup -1} of LHC data. Unitarity restoration requires that the masses and couplings of the resonances obey certain sum rules.more » We discuss the prospects for their experimental verification at the LHC.« less
  • Recently, Higgsless models of electroweak symmetry breaking have been proposed. Based on compactified five-dimensional gauge theories, these models achieve unitarity of electroweak boson self-interactions through the exchange of a tower of massive vector bosons rather than the exchange of a scalar Higgs boson. In this paper, using deconstruction, we analyze the form of the corrections to the electroweak interactions in a large class of these models, allowing for arbitrary 5-D geometry, position-dependent gauge coupling, and brane kinetic-energy terms. We show that many models considered in the literature, including those most likely to be phenomenologically viable, are in this class. Bymore » analyzing the asymptotic behavior of the correlation function of gauge currents at high momentum, we extract the exact form of the relevant correlation functions at tree level and compute the corrections to precision electroweak observables in terms of the spectrum of heavy vector bosons. We determine when nonoblique corrections due to the interactions of fermions with the heavy vector bosons become important, and specify the form such interactions can take. In particular, we find that in this class of models, so long as the theory remains unitary, S-4cos{sup 2}{theta}{sub W}T>O(1), where S and T are the usual oblique parameters. We concur with the result of Cacciapaglia et al. that small or negative S is possible--though only at the expense of substantial negative T at tree level. Although we stress our results as they apply to continuum 5-D models, they apply also to models of extended electroweak gauge symmetries motivated by models of hidden local symmetry.« less
  • We calculate the tree-level oblique corrections to electroweak precision observables generated in Higgless models of electroweak symmetry breaking with a 5D SU(2){sub L}xSU(2){sub R}xU(1){sub B-L} gauge group on a warped background. In the absence of brane induced kinetic terms (and equal left and right gauge couplings) we find the S parameter to be {approx}1.15, while T{approx}U{approx}0, as in technicolor theories. Planck brane induced kinetic terms and unequal left-right couplings can lower S, however for sufficiently low values of S tree-level unitarity will be lost. A kinetic term localized on the TeV brane for SU(2){sub D} will generically increase S, howevermore » an induced kinetic term for U(1){sub B-L} on the TeV brane will lower S. With an appropriate choice of the value of this induced kinetic term S{approx}0 can be achieved. In this case the mass of the lowest Z{sup '} mode will be lowered to about 300 GeV.« less