scholarly journals Genuine Dilatons in Gauge Theories

Universe ◽  
2020 ◽  
Vol 6 (7) ◽  
pp. 96 ◽  
Author(s):  
R. J. Crewther
Keyword(s):  
Higgs Boson ◽  
Gauge Theories ◽  
Energy Momentum Tensor ◽  
Gauge Coupling ◽  
Momentum Tensor ◽  
Boson Mass ◽  
Light Higgs Boson ◽  
Dimensional Transmutation ◽  
Low Energies ◽  
Scale Perturbation

A genuine dilaton σ allows scales to exist even in the limit of exact conformal invariance. In gauge theories, these may occur at an infrared fixed point (IRFP) α IR through dimensional transmutation. These large scales at α IR can be separated from small scales produced by θ μ μ , the trace of the energy-momentum tensor. For quantum chromodynamics (QCD), the conformal limit can be combined with chiral S U ( 3 ) × S U ( 3 ) symmetry to produce chiral-scale perturbation theory χ PT σ , with f 0 ( 500 ) as the dilaton. The technicolor (TC) analogue of this is crawling TC: at low energies, the gauge coupling α goes directly to (but does not walk past) α IR , and the massless dilaton at α IR corresponds to a light Higgs boson at α ≲ α IR . It is suggested that the W ± and Z 0 bosons set the scale of the Higgs boson mass. Unlike crawling TC, in walking TC, θ μ μ produces all scales, large and small, so it is hard to argue that its “dilatonic” candidate for the Higgs boson is not heavy.

scholarly journals The LHC Higgs boson discovery: Implications for Finite Unified Theories

2014 ◽  
Vol 29 (18) ◽  
pp. 1430032 ◽  
Author(s):  
S. Heinemeyer ◽  
M. Mondragón ◽  
G. Zoupanos
Keyword(s):  
Higgs Boson ◽  
Predictive Power ◽  
Low Energy ◽  
Boson Mass ◽  
Higgs Boson Mass ◽  
Light Higgs Boson ◽  
Quark Masses ◽  
Grand Unified Theories ◽  
Unified Theories ◽  
Discovery Potential

Finite Unified Theories (FUTs) are N = 1 supersymmetric Grand Unified Theories (GUTs) which can be made finite to all-loop orders, based on the principle of reduction of couplings, and therefore are provided with a large predictive power. We confront the predictions of an SU(5) FUT with the top and bottom quark masses and other low-energy experimental constraints, resulting in a relatively heavy SUSY spectrum, naturally consistent with the nonobservation of those particles at the LHC. The light Higgs boson mass is automatically predicted in the range compatible with the Higgs discovery at the LHC. Requiring a light Higgs boson mass in the precise range of Mh= 125.6 ±2.1 GeV favors the lower part of the allowed spectrum, resulting in clear predictions for the discovery potential at current and future pp, as well as future e+e-colliders.

scholarly journals Improving fermion mass hierarchy in grand gauge–Higgs unification with localized gauge kinetic terms

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Nobuhito Maru ◽  
Yoshiki Yatagai
Keyword(s):  
Higgs Boson ◽  
Top Quark ◽  
Gauge Coupling ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Boson Mass ◽  
Fermion Mass ◽  
Mass Hierarchy ◽  
Higgs Boson Mass ◽  
Fermion Masses

AbstractGrand gauge–Higgs unification of five dimensional SU(6) gauge theory on an orbifold $$S^1/Z_2$$ S 1 / Z 2 with localized gauge kinetic terms is discussed. The Standard model (SM) fermions on one of the boundaries and some massive bulk fermions coupling to the SM fermions on the boundary are introduced, so that they respect an SU(5) symmetry structure. The SM fermion masses including top quark are reproduced by mild tuning the bulk masses and parameters of the localized gauge kinetic terms. Gauge coupling universality is not guaranteed by the presence of the localized gauge kinetic terms and it severely constrains the Higgs vacuum expectation value. Higgs potential analysis shows that the electroweak symmetry breaking occurs by introducing additional bulk fermions in simplified representations. The localized gauge kinetic terms enhance the magnitude of the compactification scale, which helps Higgs boson mass large. Indeed the observed Higgs boson mass 125 GeV is obtained.

scholarly journals DARK MATTER WITH VARIABLE MASSES

1993 ◽  
Vol 02 (01) ◽  
pp. 85-95 ◽  
Author(s):  
JUAN GARCÍA-BELLIDO
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Cold Dark Matter ◽  
Spiral Galaxies ◽  
Energy Momentum Tensor ◽  
Gauge Coupling ◽  
Momentum Tensor ◽  
Primordial Nucleosynthesis ◽  
Effective Theories ◽  
Dilaton Coupling

String effective theories contain a dilaton scalar field which couples to gravity, matter and radiation. In general, particle masses will have different dilaton couplings. We can always choose a conformal frame in which baryons have constant masses while (nonbaryonic) dark matter have variable masses, in the context of a scalar-tensor gravity theory. We are interested in the phenomenology of this scenario. Dark matter with variable masses could have a measurable effect on the dynamical motion of the halo of spiral galaxies, which may affect cold dark matter models of galaxy formation. As a consequence of variable masses, the energy-momentum tensor is not conserved; there is a dissipative effect, due to the dilaton coupling, associated with a “dark entropy” production. In particular, if axions had variable masses they could be diluted away, thus opening the “axion window.” Assuming that dark matter with variable masses dominates the cosmological evolution during the matter era, it will affect the primordial nucleosynthesis predictions on the abundances of light elements. Furthermore, the dilaton also couples to radiation in the form of a variable gauge coupling. Experimental bounds will constrain the parameters of this model.

scholarly journals Two-point function of the energy-momentum tensor and generalised conformal structure

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
Claudio Corianò ◽  
Luigi Delle Rose ◽  
Kostas Skenderis
Keyword(s):  
Gauge Theories ◽  
Energy Momentum Tensor ◽  
Conformal Structure ◽  
Momentum Tensor ◽  
Usual Sense ◽  
Conformal Field Theories ◽  
Point Function ◽  
Conformal Field ◽  
Multiplicative Factor ◽  
Dimensionless Coupling

AbstractTheories with generalised conformal structure contain a dimensionful parameter, which appears as an overall multiplicative factor in the action. Examples of such theories are gauge theories coupled to massless scalars and fermions with Yukawa interactions and quartic couplings for the scalars in spacetime dimensions other than 4. Many properties of such theories are similar to that of conformal field theories (CFT), and in particular their 2-point functions take the same form as in CFT but with the normalisation constant now replaced by a function of the effective dimensionless coupling g constructed from the dimensionful parameter and the distance separating the two operators. Such theories appear in holographic dualities involving non-conformal branes and this behaviour of the correlators has already been observed at strong coupling. Here we present a perturbative computation of the two-point function of the energy-momentum tensor to two loops in dimensions $$d= 3, 5$$ d = 3 , 5 , confirming the expected structure and determining the corresponding functions of g to this order, including the effects of renormalisation. We also discuss the $$\hbox {d}=4$$ d = 4 case for comparison. The results for $$d=3$$ d = 3 are relevant for holographic cosmology, and in this case we also study the effect of a $$\Phi ^6$$ Φ 6 coupling, which while marginal in the usual sense it is irrelevant from the perspective of the generalised conformal structure. Indeed, the effect of such coupling in the 2-point function is washed out in the IR but it modifies the UV.

The trace anomaly and the energy momentum tensor in lattice gauge theories

1990 ◽  
Vol 16 ◽  
pp. 557-558
Author(s):  
Sergio Caracciolo ◽  
Giuseppe Curci ◽  
Pietro Menotti ◽  
Andrea Pelissetto
Keyword(s):  
Gauge Theories ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Lattice Gauge ◽  
Trace Anomaly ◽  
Lattice Gauge Theories
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