scholarly journals Gauge-invariant three-boson vertices and their Ward identities in the standard model

1995 ◽  
Vol 52 (4) ◽  
pp. 2355-2378 ◽  
Author(s):  
Joannis Papavassiliou ◽  
Kostas Philippides
Keyword(s):  
Standard Model ◽  
Ward Identities ◽  
Gauge Invariant ◽  
The Standard Model

Anomalies, instantons and axions

2018 ◽  
Author(s):  
Michael Kachelriess
Keyword(s):  
Standard Model ◽  
Path Integral ◽  
Electric Charge ◽  
Gauge Invariant ◽  
Axial Anomaly ◽  
Yang Mills ◽  
Integral Measure ◽  
The Standard Model ◽  
Electroweak Sector

The axial anomaly is derived both from the non-invariance of the path-integral measure under UA(1) transformations and calculations of specific triangle diagrams. It is demonstrated that the anomalous terms are cancelled in the electroweak sector of the standard model, if the electric charge of all fermions adds up to zero. The CP-odd term F̃μν‎Fμν‎ introduced by the axial anomaly is a gauge-invariant renormalisable interaction which is also generated by instanton transitions between Yang–Mills vacua with different winding numbers. The Peceei–Quinn symmetry is discussed as a possible explanation why this term does not contribute to the QCD action.

scholarly journals Pair production processes and flavor in gauge-invariant perturbation theory

2017 ◽  
Vol 32 (38) ◽  
pp. 1750212 ◽  
Author(s):  
Larissa Egger ◽  
Axel Maas ◽  
René Sondenheimer
Keyword(s):  
Perturbation Theory ◽  
Standard Model ◽  
Pair Production ◽  
Bound State ◽  
Gauge Invariant ◽  
Quantum Numbers ◽  
The Standard Model ◽  
Invariant States ◽  
The Impact ◽  
Invariant Perturbation Theory

Gauge-invariant perturbation theory is an extension of ordinary perturbation theory which describes strictly gauge-invariant states in theories with a Brout–Englert–Higgs effect. Such gauge-invariant states are composite operators which have necessarily only global quantum numbers. As a consequence, flavor is exchanged for custodial quantum numbers in the Standard Model, recreating the fermion spectrum in the process. Here, we study the implications of such a description, possibly also for the generation structure of the Standard Model. In particular, this implies that scattering processes are essentially bound-state–bound-state interactions, and require a suitable description. We analyze the implications for the pair-production process [Formula: see text] at a linear collider to leading order. We show how ordinary perturbation theory is recovered as the leading contribution. Using a PDF-type language, we also assess the impact of sub-leading contributions. To lowest order, we find that the result is mainly influenced by how large the contribution of the Higgs at large [Formula: see text] is. This gives an interesting, possibly experimentally testable, scenario for the formal field theory underlying the electroweak sector of the Standard Model.

scholarly journals About electrodynamics, standard model and the quantization of the electrical charge

2018 ◽  
Vol 33 (33) ◽  
pp. 1850205
Author(s):  
Renata Jora
Keyword(s):  
Partition Function ◽  
Standard Model ◽  
Gauge Field ◽  
Consistency Condition ◽  
Field Method ◽  
Electrical Charge ◽  
Ward Identities ◽  
Anomaly Cancellation ◽  
Cancellation Condition ◽  
The Standard Model

The quantization of the electrical charge in the electrodynamics and of the hypercharge in the standard model are imposed in the theory based not on theoretical arguments but on the experimental observations. In this paper we propose a quantum consistency condition in a theory where Ward identities are respected that requires the quantization of the charge within the framework of the theory without external impositions. This refers to the renormalization conditions in the background gauge field method such that to ensure a correct mathematical correspondence between the bare partition function and the renormalized one. Applied to the standard model of elementary particles our criterion together with the anomaly cancellation condition leads to the correct hypercharge assignment of all standard model fermions.

scholarly journals Decays Z → γγ and Z → gg in the Standard Model Extension

2015 ◽  
Vol 30 (35) ◽  
pp. 1550216 ◽  
Author(s):  
J. Castro-Medina ◽  
H. Novales-Sanchez ◽  
J. J. Toscano ◽  
E. S. Tututi
Keyword(s):  
Standard Model ◽  
Background Field ◽  
Standard Model Extension ◽  
Gauge Invariant ◽  
Spatial Component ◽  
Loop Level ◽  
Model Extension ◽  
The Standard Model ◽  
Decay Widths ◽  
The One

The [Formula: see text] and [Formula: see text] decays are studied in the context of the renormalizable version of the Standard Model Extension. The [Formula: see text]-odd [Formula: see text] bilinear interaction, which involves the constant background field [Formula: see text] and which has been a subject of interest in literature, is considered. It is shown that the [Formula: see text] and [Formula: see text] decays, which are strictly zero in the standard model, can be generated radiatively at the one-loop level. It is found that these decays are gauge invariant and free of ultraviolet divergences, and that the corresponding decay widths only depend on the spatial component of the background field [Formula: see text].

scholarly journals COULOMB'S LAW CORRECTIONS FROM A GAUGE-KINETIC MIXING

2011 ◽  
Vol 26 (05) ◽  
pp. 863-871 ◽  
Author(s):  
PATRICIO GAETE ◽  
IVÁN SCHMIDT
Keyword(s):  
Standard Model ◽  
Coulomb Potential ◽  
Wilson Loop ◽  
Quantum Potential ◽  
Gauge Invariant ◽  
Hidden Sector ◽  
The Standard Model ◽  
Dependent Variables ◽  
Path Dependent ◽  
Coulomb's Law

We study the connection or equivalence between two well-known extensions of the Standard Model, that is, for the coupling between the familiar massless electromagnetism U (1) QED and a hidden-sector U (1)h, and axionic electrodynamics. Our discussion is carried out using the gauge-invariant but path-dependent variables formalism, which is an alternative to the Wilson loop approach. When we compute in this way the static quantum potential for the coupling between the familiar massless electromagnetism U (1) QED and a hidden-sector U (1)h, the result of this calculation is a Yukawa correction to the usual static Coulomb potential. Previously,14, we have shown that axionic electrodynamics has a different structure which is reflected in a confining piece. Therefore, both extensions of the Standard Model are not equivalent. Interestingly, when the above calculation is done inside a superconducting box, the Coulombic piece disappears leading to a screening phase.

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