Infrared quasi-fixed point structure of the fermion masses in the standard model: The two-loop analysis

1988 ◽  
Vol 37 (3) ◽  
pp. 413-423 ◽  
Author(s):  
P. Krawczyk ◽  
M. Olechowski
Keyword(s):  
Fixed Point ◽  
Standard Model ◽  
Loop Analysis ◽  
Fermion Masses ◽  
The Standard Model

TOP OFF THE UNPARTICLE

2008 ◽  
Vol 23 (16n17) ◽  
pp. 2579-2590 ◽  
Author(s):  
DEBAJYOTI CHOUDHURY ◽  
DILIP KUMAR GHOSH
Keyword(s):  
Fixed Point ◽  
Standard Model ◽  
Top Physics ◽  
Energy Scale ◽  
Scale Invariant ◽  
The Standard Model

The existence of an exactly scale invariant sector possessing a nontrivial infrared fixed point at a higher energy scale and its possible communication with the Standard Model particles through a heavy messenger sector has been shown to lead to curious unparticle effects. We demonstrate that top physics at the Tevatron can already constrain such theories. We also consider possible improvements at the LHC and delineate some striking signatures.

scholarly journals Investigating BSM Models with Large Scale Separation

2018 ◽  
Vol 175 ◽  
pp. 08007 ◽  
Author(s):  
Anna Hasenfratz ◽  
Claudio Rebbi ◽  
Oliver Witzel
Keyword(s):  
Fixed Point ◽  
Standard Model ◽  
Large Scale ◽  
Gauge Coupling ◽  
Model Systems ◽  
Beyond The Standard Model ◽  
Heavy Flavor ◽  
Scale Separation ◽  
The Standard Model ◽  
Effective Description

Mass-split systems based on a conformal infrared fixed point provide a lowenergy effective description of beyond the standard model systems with large scale separation. We report results of exploratory investigations with four light and eight heavy flavors using staggered fermions, and up to five different values for the light flavor mass, five different heavy flavor masses, and two values of the bare gauge coupling.

Seesaw fermion masses in the standard model

1989 ◽  
Vol 39 (1) ◽  
pp. 351-353 ◽  
Author(s):  
Subhash Rajpoot
Keyword(s):  
Standard Model ◽  
Fermion Masses ◽  
The Standard Model

scholarly journals Lattice studies of quantum chromodynamics-like theories with many fermionic degrees of freedom

2011 ◽  
Vol 369 (1946) ◽  
pp. 2701-2717 ◽  
Author(s):  
Thomas DeGrand
Keyword(s):  
Fixed Point ◽  
Standard Model ◽  
Quantum Chromodynamics ◽  
Degrees Of Freedom ◽  
Gauge Theories ◽  
Gauge Coupling ◽  
Higgs Sector ◽  
Intrinsic Interest ◽  
The Standard Model

I give an elementary introduction to the study of gauge theories coupled to fermions with many degrees of freedom. Besides their intrinsic interest, these theories are candidates for non-perturbative extensions of the Higgs sector of the standard model. While related to quantum chromodynamics, these systems can exhibit very different behaviour from it: they can possess a running gauge coupling with an infrared-attractive fixed point. I briefly survey recent lattice work in this area.

scholarly journals Comments on gauge anomalies at dimension-six in the Standard Model Effective Field Theory

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Quentin Bonnefoy ◽  
Luca Di Luzio ◽  
Christophe Grojean ◽  
Ayan Paul ◽  
Alejo N. Rossia
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Effective Field Theory ◽  
Effective Field ◽  
Goldstone Bosons ◽  
Fermion Masses ◽  
Higher Dimensional ◽  
The Standard Model ◽  
Gauge Anomalies ◽  
Working Out

Abstract We study whether higher-dimensional operators in effective field theories, in particular in the Standard Model Effective Field Theory (SMEFT), can source gauge anomalies via the modification of the interactions involved in triangle diagrams. We find no evidence of such gauge anomalies at the level of dimension-6 operators that can therefore be chosen independently to each others without spoiling the consistency of SMEFT, at variance with recent claims. The underlying reason is that gauge-invariant combinations of Goldstone bosons and massive gauge fields are allowed to couple to matter currents which are not conserved. We show this in a toy model by computing the relevant triangle diagrams, as well as by working out Wess-Zumino terms in the bosonic EFT below all fermion masses. The same approach applies directly to the Standard Model both at the renormalisable level, providing a convenient and unusual way to check that the SM is anomaly free, as well as at the non-renormalisable level in SMEFT.

scholarly journals Gravity Dictates the Number of Fermion Generations: 3

2020 ◽  
Author(s):  
Stephane Maes
Keyword(s):  
Standard Model ◽  
Fractal Structure ◽  
Classical Model ◽  
Massive Gravity ◽  
Higgs Bosons ◽  
Surprising Result ◽  
Virtual Particles ◽  
Fermion Masses ◽  
The Standard Model ◽  
Open Issues

In a multi-fold universe, gravity emerges from Entanglement through the multi-fold mechanisms. As a result, gravity-like effects appear in between entangled particles that they be real or virtual. Long range, massless gravity results from entanglement of massless virtual particles. Entanglement of massive virtual particles leads to massive gravity contributions at very smalls scales. Multi-folds mechanisms also result into a spacetime that is discrete, with a random walk fractal structure and non-commutative geometry that is Lorentz invariant and where spacetime nodes and particles can be modeled with microscopic black holes. All these recover General relativity at large scales and semi-classical model remain valid till smaller scale than usually expected. Gravity can therefore be added to the Standard Model. This can contribute to resolving several open issues with the Standard Model. It has always been intriguing to explain why there seems to be only 3 generations of Fermions, for each family, including neutrinos. In this paper, we show that there are only 3 regimes defined in the Standard Model Lagrangian complemented with gravity, when it comes to the contribution of fermion masses interacting with Higgs bosons. As a result, differentiations of mass implies only 3 generations. It is another surprising result, from adding non-negligible gravity to the Standard model. While shown in the context of a multi-fold universe, the result can be extended to any model where gravity is not negligible at small scales.

scholarly journals Fermion masses and the standard model group as a diagonal subgroup

1994 ◽  
Vol 420 (1-2) ◽  
pp. 3-46 ◽  
Author(s):  
C.D. Froggatt ◽  
G. Lowe ◽  
H.B. Nielsen
Keyword(s):  
Standard Model ◽  
Model Group ◽  
Fermion Masses ◽  
The Standard Model ◽  
Diagonal Subgroup

scholarly journals SO(10) UNIFICATION IN NONCOMMUTATIVE GEOMETRY REVISITED

1999 ◽  
Vol 14 (04) ◽  
pp. 559-588 ◽  
Author(s):  
RAIMAR WULKENHAAR
Keyword(s):  
Standard Model ◽  
Noncommutative Geometry ◽  
Mass Term ◽  
Tree Level ◽  
Model Structure ◽  
Fermion Masses ◽  
The Standard Model ◽  
The Right ◽  
Higgs Fields ◽  
Algebraic Formulation

We investigate the SO(10) unification model in a Lie-algebraic formulation of noncommutative geometry. The SO(10) symmetry is broken by a 45-Higgs and the Majorana mass term for the right neutrinos (126-Higgs) to the standard model structure group. We study the case where the fermion masses are as general as possible, which leads to two 10-multiplets, four 120-multiplets and two additional 126-multiplets of Higgs fields. This Higgs structure differs considerably from the two Higgs multiplets 16 ⊗ 16* and 16c ⊗ 16* used by Chamseddine and Fröhlich. We find the usual tree level predictions of noncommutative geometry: [Formula: see text], [Formula: see text] and g2=g3 as well as mH≤ mt.

scholarly journals FERMION MASSES AND MIXINGS IN GAUGE THEORIES

2002 ◽  
Vol 17 (28) ◽  
pp. 3981-4006 ◽  
Author(s):  
D. FALCONE
Keyword(s):  
Gauge Symmetry ◽  
Standard Model ◽  
Neutrino Mass ◽  
Quark Mass ◽  
Gauge Theories ◽  
Neutrino Oscillations ◽  
Heavy Neutrino ◽  
Fermion Masses ◽  
Mass Matrices ◽  
The Standard Model

The recent evidence for neutrino oscillations stimulate us to discuss again the problem of fermion masses and mixings in gauge theories. In the standard model, several forms for quark mass matrices are equivalent. They become ansatze within most extensions of the standard model, where also relations between quark and lepton sectors may hold. In a seesaw framework, these relations can constrain the scale of heavy neutrino mass, which is often related to the scale of intermediate or unification gauge symmetry. As a consequence, two main scenarios arise. Hierarchies of masses and mixings may be explained by broken horizontal symmetries.

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