A dynamical symmetry breaking model of electroweak interactions is
investigated based on strongly interacting fermions. Vector-like fermions of
different representations of the weak SU(2) form a symmetry breaking condensate
and generate the lepton and quark masses. The weak gauge bosons get their usual
standard model masses from a gauge invariant effective Lagrangian of a doublet
scalar field composed of the new fermion fields. Gap equations are derived and
the conditions for finding a symmetry breaking solution are presented. The
parameters of the model are constrained further by perturbative unitarity. The
oblique electroweak corrections only slightly constrain the model. It is shown
that the new charged fermions are produced at the next linear colliders in
large number and the cross section for the LHC is presented.Comment: 27 pages, 11 figure

Cynolter, G.

Lendvai, E.

English

arXiv

We propose and analyze an alternative model of dynamical electroweak symmetry breaking. In the Standard Model of electroweak interactions the elementary Higgs fiel and the Higgs sector are replaced by vector-like fermions and their interactions. The new fermions are a weak doublet and a singlet. They have kinetic terms with covariant derivatives and gauge invariant four-fermion interactions. The model is a low energy effective one with a natural cutoff in the TeV regime. Due to the quartic fermion couplings the new fermions form condensates. The new fermions mix in one condensate and the mixing breaks the electroweak symmetry. The condensates contribute to the masses of the new femions, which may or may not have mass terms in the original Lagrangian. Gap equations are derived for the masses of the new fermions and the conditions are presented for mass generations and electroweak symmetry breaking. In the spectrum there are two neutral fermions and a charged one with mass between the neutral ones. The new sector can be described by three parameters, these are the two neutral masses and the mixing angle. These parameters are further constrained by the unitarity of two particle scattering amplitudes, providing an upper bound for the lighter neutral mass depending on the cutoff of the model. The standard chiral fermions get their masses via interactions with the condensing new fermions, but there is no mixing between the standard and the new fermions. There is an effective composite scalar in the model at low energies, producing the weak gauge boson masses in effective interactions. The ρ parameter is one at leading order. The model can be constrained by one-loop oblique corrections. The Peskin-Takeuchi S and T parameters are calculated in the model. The parameters of the model are only slightly constrained, the T parameter requires the new neutral fermion masses not to be very far from each other, allowing higher mass difference for higher masses and smaller mixing. The S parameter gives practically no constraints on the masses. The new fermions can give positive contributions to T allowing for a heavy Higgs in the precision electroweak tests. It is shown that the new fermions will be copiously produced at the next generation of linear colliders and cross sections are presented for the Large Hadron Collider. An additional nice feature of the model is that the lightest new neutral fermion is an ideal and natural dark matter candidate. © 2012 by Nova Science Publishers, Inc. All rights reserved

Cynolter, G

Lendvai, E

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Fermion condensate as Higgs substitute

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Fermion Condensate as Higgs substitute

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