scholarly journals Holographic models of composite Higgs in the Veneziano limit. Part I. Bosonic sector

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Daniel Elander ◽  
Michele Frigerio ◽  
Marc Knecht ◽  
Jean-Loïc Kneur
Keyword(s):  
Symmetry Breaking ◽  
Gauge Theories ◽  
Scale Invariant ◽  
Strongly Coupled ◽  
Mass Gap ◽  
Composite Higgs ◽  
Holographic Approach ◽  
Scaling Dimension ◽  
Invariant Gauge ◽  
Domain Of Validity

Abstract We study strongly-coupled, approximately scale-invariant gauge theories, which develop a mass gap in the infrared. We argue that a large number of fermion flavours is most suitable to provide an ultraviolet completion for the composite Higgs scenario. The holographic approach allows to describe the qualitative features of the non-perturbative dynamics in the Veneziano limit. We introduce new bottom-up holographic models, which incorporate the backreaction of flavour on the geometry, and show that this can correlate the mass gap to the scale of flavour-symmetry breaking. We compute the mass spectrum for the various composite bosonic states, and study its dependence on the scaling dimension of the symmetry-breaking operators, as well as on the number of flavours. The different regions with a light dilaton are critically surveyed. We carefully assess the domain of validity of the holographic approach, and compare it with lattice simulations and the Nambu-Jona-Lasinio model.

scholarly journals Holography of Strongly Coupled Gauge Theories

2022 ◽  
Vol 258 ◽  
pp. 08001
Author(s):  
Nick Evans
Keyword(s):  
Symmetry Breaking ◽  
Chiral Symmetry ◽  
Periodic Table ◽  
Gauge Theories ◽  
Chiral Symmetry Breaking ◽  
Higher Dimension ◽  
Bottom Up ◽  
Strongly Coupled ◽  
Composite Higgs

The "periodic table" of strongly coupled gauge theories remains only sketchily understood. Holography has developed to the point where bottom up constructions can describe the spectrum of individual gauge theories (based on assumptions of their running) including quarks in different representations and higher dimension operators. I highlight the method with a "perfected" version of an AdS dual of QCD and results for composite higgs models with two representations of quarks. The method raises questions about the degree to which energy scales can be split in generic gauge theories including whether confinement and chiral symmetry breaking are linked.

scholarly journals CONFORMAL HIGGS, OR TECHNI-DILATON — COMPOSITE HIGGS NEAR CONFORMALITY

2010 ◽  
Vol 25 (27n28) ◽  
pp. 5128-5144 ◽  
Author(s):  
KOICHI YAMAWAKI
Keyword(s):  
Goldstone Boson ◽  
Gluon Condensate ◽  
Bound State ◽  
Fermion Mass ◽  
Scale Invariant ◽  
Mass Generation ◽  
Composite Higgs ◽  
Njl Model ◽  
Holographic Approach ◽  
Intrinsic Scale

In contrast to the folklore that Technicolor (TC) is a "Higgsless theory", we shall discuss existence of a composite Higgs boson, Techni-Dilaton (TD), a pseudo-Nambu-Goldstone boson of the scale invariance in the Scale-invariant/Walking/Conformal TC (SWC TC) which generates a large anomalous dimension γm ≃ 1 in a wide region from the dynamical mass [Formula: see text] of the techni-fermion all the way up to the intrinsic scale ΛTC of the SWC TC (analogue of ΛQCD), where ΛTC is taken typically as the scale of the Extended TC scale Λ ETC : Λ TC ≃ Λ ETC ~ 103 TeV (≫ m). All the techni-hadrons have mass on the same order [Formula: see text], which in SWC TC is extremely smaller than the intrinsic scale Λ TC ≃ Λ ETC , in sharp contrast to QCD where both are of the same order. The mass of TD arises from the non-perturbative scale anomaly associated with the techni-fermion mass generation and is typically 500-600 GeV, even smaller than other techni-hadrons of the same order of [Formula: see text], in another contrast to QCD which is believed to have no scalar [Formula: see text] bound state lighter than other hadrons. We discuss the TD mass in various methods, Gauged NJL model via ladder Schwinger-Dyson (SD) equation, straightforward calculations in the ladder SD/ Bethe-Salpeter equation, and the holographic approach including techni-gluon condensate. The TD may be discovered in LHC.

scholarly journals STRONGLY COUPLED N=1 SUPERSYMMETRIC SO(Nc) GAUGE THEORIES WITHOUT MAGNETIC DEGREES OF FREEDOM

2004 ◽  
Vol 19 (25) ◽  
pp. 4323-4354
Author(s):  
MASAKI YASUÈ
Keyword(s):  
Symmetry Breaking ◽  
Degrees Of Freedom ◽  
Gauge Theories ◽  
Low Energy ◽  
Flavor Symmetry ◽  
Correct Description ◽  
Strongly Coupled ◽  
Energy Physics

In strongly coupled supersymmetric SO (Nc) gauge theories with Nf-quarks for Nc-2≤Nf(≤3(Nc-2)/2), their low-energy physics can be described by Nambu–Goldstone superfields associated with dynamical flavor symmetry breaking, which should be compared with the absence of flavor symmetry breaking in the conventional description in terms of magnetic degrees of freedom. The presence of the flavor symmetry breaking is confirmed by the well-known instanton effects in SO (Nc) with Nf=Nc-2, which are also described by our proposed effective superpotential. For Nf≥Nc-1, our effective superpotentials utilize baryonic configurations as well as mesons composed of two quarks. The baryonic configurations are supplied by "diquarks" made of Nc-1 quarks for Nf=Nc-1 and by baryons composed of Nc quarks for Nc≥Nf. It is argued that our effective superpotentials exhibit the holomorphic decoupling property, the anomaly-matching property and correct description of instanton effects in SO (Nc) when Nf-Nc+2 quarks become massive if Nf≥Nc-1.

scholarly journals Strong dynamics, composite Higgs and the conformal window

2016 ◽  
Vol 31 (22) ◽  
pp. 1643003 ◽  
Author(s):  
Daniel Nogradi ◽  
Agostino Patella
Keyword(s):  
Mass Spectrum ◽  
Symmetry Breaking ◽  
Recent Progress ◽  
Gauge Theories ◽  
Model Building ◽  
Dynamical Symmetry ◽  
Higgs Particle ◽  
Abelian Gauge ◽  
Composite Higgs

We review recent progress in the lattice investigations of near-conformal non-Abelian gauge theories relevant for dynamical symmetry breaking and model building of composite Higgs models. The emphasis is placed on the mass spectrum and the running renormalized coupling. The role of a light composite scalar isosinglet particle as a composite Higgs particle is highlighted.

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