scholarly journals THEORY OF ELECTROWEAK INTERACTIONS WITHOUT SPONTANEOUS SYMMETRY BREAKING

2001 ◽  
Vol 16 (25) ◽  
pp. 4171-4188 ◽  
Author(s):  
BING AN LI
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Z Boson ◽  
W Boson ◽  
Axial Vector ◽  
Fermion Mass ◽  
Electroweak Theory ◽  
Intermediate Boson ◽  
Generating Functional ◽  
Fermion Masses

An electroweak theory without spontaneous symmetry breaking is studied in this paper. A new symmetry breaking of SU (2)L × U (1), axial-vector symmetry breaking, caused by the combination of the axial-vector component of the intermediate boson and the fermion mass is found in electroweak theory. The mass of the W boson is resulted in the combination of the axial-vector symmetry breaking and the explicit symmetry breaking by the fermion masses. The Z boson gains mass from the axial-vector symmetry breaking only. [Formula: see text], [Formula: see text], and [Formula: see text] are obtained. They are in excellent agreement with data. The SU (2)L × U (1) invariant generating functional of the Green functions is constructed and the theory is proved to be renormalizable.

Masses of W and Z bosons without spontaneous symmetry breaking

2001 ◽  
Vol 16 (supp01a) ◽  
pp. 351-353
Author(s):  
Bing An Li
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Axial Vector ◽  
Z Bosons ◽  
Dynamical Symmetry ◽  
Fermion Mass ◽  
Electroweak Theory ◽  
Dynamical Symmetry Breaking ◽  
Vector Component ◽  
The Masses

A new dynamical symmetry breaking of SU(2)L × U(1) caused by the combination of the axial-vector component and the fermion mass is found in electroweak theory. The masses of the W and the Z bosons are obtained to be [Formula: see text] and [Formula: see text]. The Fermi constant is determined to be [Formula: see text].

scholarly journals ON FERMION ZERO MODES IN INSTANTON V - A MODELS WITH SPONTANEOUS SYMMETRY BREAKING

1994 ◽  
Vol 09 (08) ◽  
pp. 715-723
Author(s):  
KAMRAN SARIRIAN
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Electroweak Theory ◽  
Yukawa Couplings ◽  
Zero Modes ◽  
Left Handed ◽  
Fermion Masses ◽  
Left And Right

The left- and right-handed fermion zero modes are examined. Their behavior under the variation of the size of the instanton, ρ I , and the size of the Higgs core, ρ H , for a range of Yukawa couplings corresponding to the fermion masses in the electroweak theory are studied. It is shown that the characteristic radii of the zero modes, in particular those of the left-handed fermions, are locked to the instanton size, and are not affected by the variation of ρ H , except for fermion masses much larger than those in the standard electroweak theory.

scholarly journals ANOMALOUS FERMION MASS GENERATION AT THREE LOOPS

2013 ◽  
Vol 28 (22) ◽  
pp. 1350083 ◽  
Author(s):  
APOSTOLOS PILAFTSIS
Keyword(s):  
Gauge Theory ◽  
Quantum Gravity ◽  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Model Building ◽  
Heavy Fermions ◽  
Fermion Mass ◽  
Mass Generation ◽  
Fermion Masses ◽  
Gravity Effects

We present a novel mechanism for generating fermion masses through global anomalies at the three-loop level. In a gauge theory, global anomalies are triggered by the possible existence of scalar or pseudoscalar states and heavy fermions, whose masses may not necessarily result from spontaneous symmetry breaking. The implications of this mass-generating mechanism for model building are discussed, including the possibility of creating low-scale fermion masses by quantum gravity effects.

WARD–TAKAHASHI IDENTITIES AND THE SPIN-0 COMPONENTS OF W AND Z FIELDS

2004 ◽  
Vol 19 (28) ◽  
pp. 4813-4823
Author(s):  
BING AN LI
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Axial Vector ◽  
The Masses

The Ward–Takahashi (WT) identities of the axial-vector currents and the charged vector currents of fermions are changed after spontaneous symmetry breaking. The spin-0 components of Z and W fields are revealed from the changed WT identities. The masses of these spin-0 components are at 1014 GeV. They are ghosts.

scholarly journals Electroweak measurements from W, Z and photon final states

2014 ◽  
Vol 31 ◽  
pp. 1460276
Author(s):  
Hang Yin ◽  
Keyword(s):  
Differential Cross Section ◽  
Cross Section ◽  
Z Boson ◽  
W Boson ◽  
Charge Asymmetry ◽  
Distribution Functions ◽  
Boson Mass ◽  
Electroweak Theory ◽  
Final States ◽  
Parton Distribution Functions

We present the most recent precision electroweak measurements of single W and Z boson cross section and properties from the LHC and Tevatron colliders, analyzing data collected by ATLAS, CDF, CMS, D0, and LHCb detectors. The results include the measurement of the single W and Z boson cross section at LHC, the differential cross section measurements, the measurement of W boson mass, the measurement of W and Z charge asymmetry. These measurements provide precision tests on the electroweak theory, high order predictions and the information can be used to constraint parton distribution functions.

Gross–Neveu–Yukawa and Gross–Neveu models

2021 ◽  
pp. 489-506
Author(s):  
Jean Zinn-Justin
Keyword(s):  
Phase Transition ◽  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Particle Physics ◽  
Continuous Phase ◽  
Two Dimensions ◽  
Fermion Mass ◽  
Dirac Fermions ◽  
Mass Generation ◽  
Four Dimensions

In this chapter, a model is considered that can be defined in continuous dimensions, the Gross– Neveu–Yukawa (GNY) model, which involves N Dirac fermions and one scalar field. The model has a continuous U(N) symmetry, and a discrete symmetry, which prevents the addition of a fermion mass term to the action. For a specific value of a coefficient of the action, the model undergoes a continuous phase transition. The broken phase illustrates a mechanism of spontaneous symmetry breaking, leading to spontaneous fermion mass generation like in the Standard Model (SM) of particle physics. In four dimensions, the GNY can be considered as a toy model to represent the interactions between the top quark and the Higgs boson, the heaviest particles of the SM of fundamental interactions, when the gauge fields are omitted. The model is renormalizable in four dimensions and its renormalization group (RG) properties can be studied in d = 4 and d = 4 − ϵ dimensions. A model of self-interacting fermions with the same symmetries and fermion content, the Gross–Neveu (GN) model, has been widely studied. In perturbation theory, for d > 2, it describes only a phase with massless fermions but, in d = 2 + ϵ dimensions, the RG indicates that, at a critical value of the coupling constant, the model experiences a phase transition. In two dimensions, it is renormalizable and exhibits the phenomenon of asymptotic freedom. The massless phase becomes infrared unstable and there is strong evidence that the spectrum corresponds to spontaneous symmetry breaking and fermion mass generation.

scholarly journals Investigation of the scalar spectrum in SU (3) with eight degenerate flavors

2017 ◽  
Vol 32 (35) ◽  
pp. 1747002 ◽  
Author(s):  
E. Rinaldi
Keyword(s):  
Axial Vector ◽  
Mass Range ◽  
Fermion Mass ◽  
Axial Vector Meson ◽  
Vector Resonance ◽  
Quantum Numbers ◽  
Fermion Masses ◽  
The One ◽  
The Masses ◽  
Fermion Action

The Lattice Strong Dynamics collaboration is investigating the properties of a SU(3) gauge theory with [Formula: see text] light fermions on the lattice. We measure the masses of the lightest pseudoscalar, scalar and vector states using simulations with the nHYP staggered-fermion action on large volumes and at small fermion masses, reaching [Formula: see text]. The axial-vector meson and the nucleon are also studied for the same range of fermion masses. One of the interesting features of this theory is the dynamical presence of a light flavor-singlet scalar state with [Formula: see text] quantum numbers that is lighter than the vector resonance and has a mass consistent with the one of the pseudoscalar state for the whole fermion mass range explored. We comment on the existence of such state emerging from our lattice simulations and on the challenges of its analysis. Moreover we highlight the difficulties in pursuing simulations in the chiral regime of this theory using large volumes.

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