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 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 Fermion mass splitting in the technicolor coupled scenario

2020 ◽  
Vol 80 (7) ◽  
Author(s):  
A. Doff ◽  
A. A. Natale
Keyword(s):  
Mass Spectrum ◽  
Goldstone Boson ◽  
Mass Splitting ◽  
Fermion Mass ◽  
Mass Generation ◽  
Family Symmetry ◽  
Composite Boson ◽  
Strongly Interacting ◽  
Light Scalar ◽  
Pseudo Goldstone Boson

Abstract We discuss fermion mass generation in unified models where QCD and technicolor (or any two strongly interacting theories) have their Schwinger–Dyson equations coupled. In this case the technicolor (TC) and QCD self-energies are modified in comparison with the behavior observed in the isolated theories. In these models the pseudo-Goldstone boson masses are much higher than the ones obtained in different contexts, and phenomenological signals, except from a light scalar composite boson, will be quite difficult to be observed at present collider energies. The most noticeable fact of these models is how the mass splitting between the different ordinary fermions is generated. We discuss how a necessary horizontal (or family) symmetry can be implemented in order to generate the mass splitting between fermions of different generations; how the fermionic mass spectrum may be modified due to GUT interactions, as well as how the mass splitting within the same fermionic generation are generated due to electroweak and GUT interactions.

scholarly journals Relaxing cosmological neutrino mass bounds with unstable neutrinos

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Miguel Escudero ◽  
Jacobo Lopez-Pavon ◽  
Nuria Rius ◽  
Stefan Sandner
Keyword(s):  
Neutrino Mass ◽  
Particle Physics ◽  
Goldstone Boson ◽  
Mass Scale ◽  
Simple Extension ◽  
Type I ◽  
Mass Generation ◽  
Age Of The Universe ◽  
Neutrino Mass Models ◽  
The Right

Abstract At present, cosmological observations set the most stringent bound on the neutrino mass scale. Within the standard cosmological model (ΛCDM), the Planck collaboration reports ∑mv< 0.12 eV at 95 % CL. This bound, taken at face value, excludes many neutrino mass models. However, unstable neutrinos, with lifetimes shorter than the age of the universe τν ≲ tU, represent a particle physics avenue to relax this constraint. Motivated by this fact, we present a taxonomy of neutrino decay modes, categorizing them in terms of particle content and final decay products. Taking into account the relevant phenomenological bounds, our analysis shows that 2-body decaying neutrinos into BSM particles are a promising option to relax cosmological neutrino mass bounds. We then build a simple extension of the type I seesaw scenario by adding one sterile state ν4 and a Goldstone boson ϕ, in which νi→ ν4ϕ decays can loosen the neutrino mass bounds up to ∑mv ∼ 1 eV, without spoiling the light neutrino mass generation mechanism. Remarkably, this is possible for a large range of the right-handed neutrino masses, from the electroweak up to the GUT scale. We successfully implement this idea in the context of minimal neutrino mass models based on a U(1)μ−τ flavor symmetry, which are otherwise in tension with the current bound on ∑mv.

scholarly journals LIGHT COMPOSITE HIGGS: LCH @ LHC

2005 ◽  
Vol 20 (27) ◽  
pp. 6133-6148 ◽  
Author(s):  
FRANCESCO SANNINO
Keyword(s):  
Gauge Group ◽  
Higgs Mass ◽  
Cold Dark Matter ◽  
Precision Measurements ◽  
Chiral Phase ◽  
Symmetric Representation ◽  
Composite Higgs ◽  
Higher Dimensional ◽  
The One ◽  
Intrinsic Scale

Here I summarize some of the salient features of technicolor theories with technifermions in higher dimensional representations of the technicolor gauge group. The expected phase diagram as function of number of flavors and colors for the two index (anti)symmetric representation of the gauge group is reviewed. After having constructed the simplest walking technicolor theory one can show that it is not at odds with the precision measurements. The simplest theory also requires, for consistency, a fourth family of heavy leptons. The latter may result in an interesting signature at LHC. In the case of a fourth family of leptons with ordinary lepton hypercharge the new heavy neutrino can be a natural candidate of cold dark matter. New theories will also be proposed in which the critical number of flavors needed to enter the conformal window is higher than in the one with fermions in the two-index symmetric representation, but lower than in the walking technicolor theories with fermions only in the fundamental representation of the gauge group. Due to the near conformal/chiral phase transition the composite Higgs is very light compared to the intrinsic scale of the technicolor theory. For the two technicolor theory the composite Higgs mass is predicted not to exceed 150 GeV.

GROUND STATE CHARGE OF FERMION SOLITON SYSTEM IN 1+1 AND 3+1 DIMENSIONS

1993 ◽  
Vol 08 (04) ◽  
pp. 705-721
Author(s):  
M. RAVENDRANADHAN ◽  
M. SABIR
Keyword(s):  
Ground State ◽  
Energy State ◽  
Flow Analysis ◽  
Background Field ◽  
Bound State ◽  
Fermion Mass ◽  
Spectral Flow ◽  
Bound State Spectrum ◽  
Spectral Asymmetry ◽  
State Charge

Ground state charge of some fermion soliton system without C-invariance is calculated in 1+1 and 3+1 dimensions by a combination of adiabatic method and spectral flow analysis. Induced charge is calculated by evolving adiabatically the fields from a vacuum having a background field which has a zero energy state and spectral symmetry. The spectral flow is calculated by an analysis of the bound state spectrum. In 1+1 dimension our calculations are in agreement with the results already found in the literature. In 3+1 dimension we study the interaction of fermions with monopoles and dyons. In the case of monopoles, even though there is spectral asymmetry, ground state charge is found to be ±1/2. It is shown that ground state charge gets contribution only from the lowest angular momentum states and is discontinuous at the fermion mass.

Unitarity Bound on the Scale of Fermion Mass Generation

1987 ◽  
Vol 59 (21) ◽  
pp. 2405-2407 ◽  
Author(s):  
T. Appelquist ◽  
M. S. Chanowitz
Keyword(s):  
Fermion Mass ◽  
Mass Generation ◽  
Unitarity Bound

SUPER SYMMETRY IN STRONG AND WEAK INTERACTIONS

2010 ◽  
Vol 19 (02) ◽  
pp. 263-280
Author(s):  
U. V. S. SESHAVATHARAM ◽  
S. LAKSHMINARAYANA
Keyword(s):  
Ground State ◽  
Crucial Role ◽  
Weak Interactions ◽  
Light Quark ◽  
Fermion Mass ◽  
Coupling Constant ◽  
Mass Generation ◽  
Super Symmetry ◽  
Charged Boson ◽  
Charged Mesons

For strong interaction two new fermion mass units 105.32 MeV and 11450 MeV are assumed. Existence of "Integral charge quark bosons", "Integral charge effective quark fermions", "Integral charge (effective) quark fermi-gluons" and "Integral charge quark boso-gluons" are assumed and their masses are estimated. It is noticed that, characteristic nuclear charged fermion is Xs · 105.32 = 938.8 MeV and corresponding charged boson is Xs(105.32/x) = 415.0 where Xs = 8.914 is the inverse of the strong coupling constant and x = 2.26234 is a new number by using which "super symmetry" can be seen in "strong and weak" interactions. 11450 MeV fermion and its boson of mass = 11450/x = 5060 MeV plays a crucial role in "sub quark physics" and "weak interaction". 938.8 MeV strong fermion seems to be the proton. 415 MeV strong boson seems to be the mother of the presently believed 493,496 and 547 MeV etc, strange mesons. With 11450 MeV fermion "effective quark-fermi-gluons" and with 5060 MeV boson "quark boso-gluon masses" are estimated. "Effective quark fermi-gluons" plays a crucial role in ground state charged baryons mass generation. Light quark bosons couple with these charged baryons to form doublets and triplets. "Quark boso-gluons" plays a crucial role in ground state neutral and charged mesons mass generation. Fine and super-fine rotational levels can be given by [I or (I/2)] power(1/4) and [I or (I/2)] power(1/12) respectively. Here, I = n(n+1) and n = 1, 2, 3, ….

scholarly journals NONPERTURBATIVE SOLUTIONS IN THE ELECTROWEAK THEORY WITH $\bar t t$ CONDENSATE AND THE t-QUARK MASS

2011 ◽  
Vol 26 (29) ◽  
pp. 4945-4958 ◽  
Author(s):  
BORIS A. ARBUZOV ◽  
IVAN V. ZAITSEV
Keyword(s):  
Satisfactory Agreement ◽  
Quark Mass ◽  
Effective Interaction ◽  
Electroweak Interaction ◽  
Higgs Doublet ◽  
Bound State ◽  
Heavy Quarks ◽  
Spontaneous Generation ◽  
Composite Higgs ◽  
Compensation Principle

We apply Bogoliubov compensation principle to the gauge electroweak interaction. The nontrivial solution of compensation equations for anomalous three-boson gauge invariant effective interaction uniquely defines its form-factor and parameters of the theory including value of gauge electroweak coupling [Formula: see text] in satisfactory agreement with the experimental value. A possibility of spontaneous generation of effective four-fermion interaction of heavy quarks is demonstrated. This interaction defines an equation for a scalar bound state of heavy quarks which serve as a substitute for the elementary scalar Higgs doublet. As a result we calculate the t-quark mass mt = 177 GeV in satisfactory agreement with the experimental value. The results strongly support idea of [Formula: see text] condensate as a source of the electroweak symmetry breaking. The approach predicts heavy composite Higgs scalar MH ≃ 1800 GeV .

Unitarity Bound on the Scale of Fermion Mass Generation

1988 ◽  
Vol 60 (15) ◽  
pp. 1589-1589 ◽  
Author(s):  
T. Appelquist ◽  
M. S. Chanowitz
Keyword(s):  
Fermion Mass ◽  
Mass Generation ◽  
Unitarity Bound
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