Ultraviolet dynamical symmetry breaking and a model of grand unification

Carpenter, J.D.; Norton, Richard; Soni, Amarjit

doi:10.1016/0370-2693(88)91236-1

Cited by 12 publications

(22 citation statements)

References 25 publications

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“…6,8 Equation (3) requires m t ~ 300 GeV in order to give Mw and Mz their observed values. Note that it appears to be impossible in this model to have a light top and a fourth family that dominates the sum in (3). This follows because experiment seems to rule out a fourth family with a light neutrino, 13 and neutrino mass cannot be accommodated in this model.…”

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confidence: 81%

“…This follows because experiment seems to rule out a fourth family with a light neutrino, 13 and neutrino mass cannot be accommodated in this model. 2,14 Whether such a large t-b mass splitting is compatible with experimental bounds on the deviation of p = Mwl Mzcos 2 0w from unity is not known. Equation (3) gives p -1 at lowest order (independent of t-b mass splitting 7 ), but there are higher-order corrections to this relation.…”

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confidence: 88%

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Properties of a composite Higgs particle in a dynamically broken formulation of the standard model

et al. 1990

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We suggest that dynamical breakdown of electroweak symmetry in an SU(3)xSU(2)xU(l) model of a single fermion family without fundamental scalars can reproduce the entire scalar sector of the standard model through fermion bound states and loop-induced couplings. The physical Higgs boson is essentially a it bound state. The top-quark and Higgs-boson masses are approximately 300 and 400 GeV, respectively. The strengths of the induced couplings among the scalars do not indicate a strongly interacting scalar sector.All experimental indications are that the standard model (SM) provides an adequate description of strong and electroweak interactions at all energy scales explored to date. Not every aspect of the SM has been tested, however. Perhaps the most crucial untested feature is the mechanism responsible for the spontaneous breakdown of electroweak symmetry. A key step toward verification of the SM would be the discovery of the physical Higgs boson (//), the one directly observable particle of the four fundamental scalars introduced into the theory to explain symmetry breaking.Should something resembling the H be discovered, however, it will have to be studied closely to determine whether it is indeed a fundamental particle. A composite H could well exist if the symmetry breaking is driven by a dynamical mechanism, rather than by fundamental scalars as in the SM. In models employing dynamical symmetry breaking (DSB), 1 the massless Goldstone states that become the longitudinal components of the W -and Z bosons are generally assumed to be fermionantifermion composites; conceivably the same dynamics that produces these composites could generate one or more composite //'s as well.In this Letter we discuss the properties of a composite Higgs boson that appears to exist in a particular electroweak model incorporating DSB. We argue that the couplings of the composite H to all other particles, when evaluated to a first approximation, are identical to the corresponding tree-level couplings of the fundamental H in the SM. Thus a composite H of this type would be very difficult to distinguish from a fundamental H.The model we consider 2 is based on the SU(3) xSU(2)xU(l) Lagrangian of the SM, minus all terms involving scalar fields. Note that omitting all reference to scalars means omitting all Yukawa couplings and scalar potential parameters. Thus, this model has fewer free parameters than the SM and, potentially, greater predictive power.We restrict our discussion to a one-family model in order to avoid complications that arise in the multifamily case, 2,3 but that are not relevant to the present discussion. As will become clear below, in order to make contact with experiment we should identify this single family with the third family (t,b,r, v r ).Unlike more conventional DSB models, particularly those based on the technicolor idea, 4 our model contains no QCD-like strong interaction at the TeV scale to which electroweak symmetry breaking is ascribed. We nevertheless assume that the symmetry-breaking selfenergies are of the...

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confidence: 81%

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confidence: 88%

Properties of a composite Higgs particle in a dynamically broken formulation of the standard model

et al. 1990

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“…1, and the extreme walking technicolor solution obtained when ! 0 [6], i.e., this is the case where the symmetry breaking is dominated by higher order interactions that are relevant at or above the TC scale, leading naturally to a very hard dynamics [16,17]. As two of us have pointed out in Ref.…”

Section: Effective Action and Fermion Self-energymentioning

confidence: 96%

“…(13), in this case will be identified with Ã ¼ m f exactly as performed in Ref. [17]. After some calculation we can write, in the limit ¼ 0, the following quadrilinear coupling …”

Section: Appendix B: Trilinear and Quadrilinear Couplings Originated mentioning

confidence: 99%

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Light composite Higgs from an effective action for technicolor

2008

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We compute an effective action for a composite Higgs boson formed by new fermions belonging to a general technicolor non-Abelian gauge theory, using a quite general expression for the fermionic selfenergy that depends on a certain parameter ( ), that defines the technicolor theory from the extreme walking behavior up to the one with a standard operator product expansion behavior. We discuss the values of the trilinear and quadrilinear scalar couplings. Our calculation spans all the possible physical possibilities for mass and couplings of the composite system. In the case of extreme walking technicolor theories we verify that it is possible to have a composite Higgs boson with a mass as light as the present experimental limit, contrary to the usual expectation of a heavy mass for the composite Higgs boson. In this case we obtain an upper limit for the Higgs boson mass, (M H Oð700Þ GeV for SUð2Þ TC ), and the experimental data on the Higgs boson mass constrain SUðNÞ TC technicolor gauge groups to be smaller than SUð10Þ TC .

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Strength of the trilinear Higgs boson coupling in technicolor models

Doff

Natale

2006

Physics Letters B

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We discuss the strength of the trilinear Higgs boson coupling in technicolor (or composite) models in a model independent way. The coupling is determined as a function of a very general ansatz for the technicolor self-energy, and turns out to be equal or smaller than the one of the standard model Higgs boson depending on the dynamics of the theory. With this trilinear coupling we estimate the cross section for Higgs boson pair production at the LHC. This measurement is quite improbable in the case of a heavy standard model Higgs boson, but it will be even worse when this boson is dynamically generated.

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Ultraviolet dynamical symmetry breaking and a model of grand unification

Cited by 12 publications

References 25 publications

Properties of a composite Higgs particle in a dynamically broken formulation of the standard model

Properties of a composite Higgs particle in a dynamically broken formulation of the standard model

Light composite Higgs from an effective action for technicolor

Strength of the trilinear Higgs boson coupling in technicolor models

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