Light Higgs bosons from a strongly interacting Higgs sector

Siringo, Fabio

doi:10.1209/epl/i2002-00116-1

Cited by 23 publications

(28 citation statements)

References 22 publications

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“…The graphs are evaluated by standard Feynman rules, with the trial functions iG and iD associated to any internal ghost and gluon line respectively, and the standard QCD vertices that can be read from the Lagrangian terms in Eqs. (17).…”

Section: Appendix A: Explicit Evaluation Of the Graphs And Numerical mentioning

confidence: 99%

“…Quite recently, the method of stationary variance [10,11] has been advocated as a powerful second order extension of the Gaaussian Effective Potential (GEP) [12][13][14][15]. The GEP is a genuine variational method and has been successfully applied to many physical problems in field theory, from scalar and electroweak theories [15][16][17][18][19][20][21][22] to superconductivity [23][24][25] and antiferromagnetism [26], but turns out to be useless for gauge interacting fermions [27]. Actually, since the GEP only contains first order terms, it is not suited for describing the minimal coupling of gauge theories that has no first-order effects.…”

Section: Introductionmentioning

confidence: 99%

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Gluon propagator in Feynman gauge by the method of stationary variance

Siringo

2014

Phys. Rev. D

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The low-energy limit of pure Yang-Mills SU (3) gauge theory is studied in Feynman gauge by the method of stationary variance, a genuine second-order variational method that is suited to deal with the minimal coupling of fermions in gauge theories. In terms of standard irreducible graphs, the stationary equations are written as a set of coupled non-linear integral equations for the gluon and ghost propagators. A physically sensible solution is found for any strength of the coupling. The gluon propagator is finite in the infrared, with a dynamical mass that decreases as a power at high energies. At variance with some recent findings in Feynman gauge, the ghost dressing function does not vanish in the infrared limit and a decoupling scenario emerges as recently reported for the Landau gauge.

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Section: Appendix A: Explicit Evaluation Of the Graphs And Numerical mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Gluon propagator in Feynman gauge by the method of stationary variance

Siringo

2014

Phys. Rev. D

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“…A fully consistent variational estimate of the optimal parameters would require the calculation of an effective potential [49,[56][57][58] or some real observable quantity, which is out of the aim of the present paper. On the other hand, by a comparison with the data of lattice simulations, we find that the weight of higher-loop corrections can be made very small by a judicious choice of masses and renormalization constants.…”

Section: Introductionmentioning

confidence: 99%

Analytic structure of QCD propagators in Minkowski space

Siringo

2016

Phys. Rev. D

105

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Analytical functions for the propagators of QCD, including a set of chiral quarks, are derived by a one-loop massive expansion in the Landau gauge, deep in the infrared. By analytic continuation, the spectral functions are studied in Minkowski space, yielding a direct proof of positivity violation and confinement from first principles.The dynamical breaking of chiral symmetry is described on the same footing of gluon mass generation, providing a unified picture. While dealing with the exact Lagrangian, the expansion is based on massive free-particle propagators, is safe in the infrared and is equivalent to the standard perturbation theory in the UV. By dimensional regularization, all diverging mass terms cancel exactly without including mass counterterms that would spoil the gauge and chiral symmetry of the Lagrangian. Universal scaling properties are predicted for the inverse dressing functions and shown to be satisfied by the lattice data. Complex conjugated poles are found for the gluon propagator, in agreement with the i-particle scenario.

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“…Our effective Lagrangian is general enough to include as particular cases the low-energy representation of dilaton models [19], composite Higgs models [20], the old electroweak chiral Lagrangian [21,22] and also trivially the Standard Model [23], and other conceivable models as long as the couplings λ 4 ϕ 3 and λ 4 ϕ 4 are of order M 2 ϕ and thus small at large energy. We explicitly exclude those models where these Higgs self-couplings take large values [24] that require further analysis. Our ω, ϕ fields are derivatively coupled as befits Goldstone bosons.…”

Section: Discussion and Outlookmentioning

confidence: 99%

Strongly interacting electroweak symmetry breaking sector with a Higgs-like light scalar

Dobado

Delgado

Llanes-Estrada

2014

AIP Conference Proceedings

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Abstract. The apparent finding of a 125-GeV light Higgs boson closes unitarity of the minimal Standard Model (SM), that is weakly interacting: this is an exceptional feature not generally true if new physics exists beyond the mass gap found at the LHC up to 700 GeV. Such new physics induces departures of the low-energy dynamics for the minimal electroweak symmetry-breaking sector, with three Goldstone bosons (related to longitudinal W bosons) and one light scalar, from the SM couplings. We calculate the scattering amplitudes among these four particles and their partial-wave projections in effective theory. For this we employ the Electroweak Chiral Lagrangian extended by one light scalar and carry out the complete oneloop computation at high energy including the counterterms needed for perturbative renormalization, of dimension eight. For most of parameter space, the scattering is strongly interacting (with the SM a remarkable exception). We therefore explore various unitarization methods, that can already be applied to the tree-level W L W L amplitude; we find and study a natural second sigma-like scalar pole there.

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Light Higgs bosons from a strongly interacting Higgs sector

Cited by 23 publications

References 22 publications

Gluon propagator in Feynman gauge by the method of stationary variance

Gluon propagator in Feynman gauge by the method of stationary variance

Analytic structure of QCD propagators in Minkowski space

Strongly interacting electroweak symmetry breaking sector with a Higgs-like light scalar

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