scholarly journals Light-front QED, Stueckelberg field and infrared divergence

2019 ◽  
Vol 34 (18) ◽  
pp. 1950141 ◽  
Author(s):  
T. R. Govindarajan ◽  
Jai D. More ◽  
P. Ramadevi
Keyword(s):  
Quantum Electrodynamics ◽  
Infrared Divergence ◽  
Light Front ◽  
Vertex Correction ◽  
Leading Order ◽  
Massless Limit ◽  
Abelian Gauge ◽  
Abelian Gauge Theory ◽  
Self Energy

Stueckelberg mechanism introduces a scalar field, known as Stueckelberg field, so that gauge symmetry is preserved in the massive Abelian gauge theory. In this work, we show that the role of the Stueckelberg field is similar to the Kulish and Faddeev coherent state approach to handle infrared (IR) divergences. We expect that the light-front quantum electrodynamics (LFQED) with Stueckelberg field must be IR finite in the massless limit of the gauge boson. We have explicitly shown the cancellation of IR divergences in the relevant diagrams contributing to self-energy and vertex correction at leading order.

scholarly journals Stuckelberg SUSY QED and infrared problem

2020 ◽  
Vol 35 (37) ◽  
pp. 2050303
Author(s):  
Radhika Vinze ◽  
T. R. Govindarajan ◽  
Anuradha Misra ◽  
P. Ramadevi
Keyword(s):  
Quantum Electrodynamics ◽  
Infrared Divergence ◽  
Matter Field ◽  
Vertex Correction ◽  
Leading Order ◽  
Massless Limit ◽  
Gauge Invariant ◽  
Self Energy ◽  
Efficient Route ◽  
Infrared Divergences

We review gauge invariant [Formula: see text] supersymmetric massive U(1) gauge theory coupled to matter and Stuckelberg superfields. We focus on the leading order self-energy and vertex correction to the matter field in the massless limit of both the U(1) vector superfield and the Stuckelberg superfield. We explicitly verify that the theory is infrared divergence free in the massless limit. Hence the Stuckelberg mechanism appears to be the efficient route to handle infrared divergences seen in supersymmetric quantum electrodynamics. Since these additional particles have very small masses they can serve as dark matter candidates through “Ultralight particles” mechanism.

scholarly journals Semi-Abelian gauge theories, non-invertible symmetries, and string tensions beyond N-ality

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Mendel Nguyen ◽  
Yuya Tanizaki ◽  
Mithat Ünsal
Keyword(s):  
Gauge Theory ◽  
Gauge Group ◽  
Lattice Theory ◽  
Lattice Gauge Theory ◽  
Global Symmetry ◽  
Leading Order ◽  
Abelian Gauge ◽  
Abelian Gauge Theory ◽  
Lattice Gauge ◽  
Abelian Lattice

Abstract We study a 3d lattice gauge theory with gauge group U(1)N−1 ⋊ SN, which is obtained by gauging the SN global symmetry of a pure U(1)N−1 gauge theory, and we call it the semi-Abelian gauge theory. We compute mass gaps and string tensions for both theories using the monopole-gas description. We find that the effective potential receives equal contributions at leading order from monopoles associated with the entire SU(N) root system. Even though the center symmetry of the semi-Abelian gauge theory is given by ℤN, we observe that the string tensions do not obey the N-ality rule and carry more detailed information on the representations of the gauge group. We find that this refinement is due to the presence of non-invertible topological lines as a remnant of U(1)N−1 one-form symmetry in the original Abelian lattice theory. Upon adding charged particles corresponding to W-bosons, such non-invertible symmetries are explicitly broken so that the N-ality rule should emerge in the deep infrared regime.

Quantum plasmadynamics: role of the electron self-energy and the vertex correction

1996 ◽  
Vol 56 (1) ◽  
pp. 95-105 ◽  
Author(s):  
D. B. Melrose ◽  
S. J. Hardy
Keyword(s):  
Ponderomotive Force ◽  
Relativistic Quantum ◽  
Electron Gas ◽  
Vertex Correction ◽  
Radiative Corrections ◽  
Self Energy ◽  
New Class ◽  
Quantum Electron ◽  
Vacuum Polarization Tensor

The linear response 4-tensor for a relativistic quantum electron gas may be calculated by reinterpreting the electron propagator in the expression for the vacuum polarization tensor as statistical averages over the electron gas. We apply a similar procedure to two other radiative corrections: the electron self-energy and the vertex correction. When the photon propagator in these expressions is interpreted as a statistical average over a distribution of waves in the medium, these radiative corrections lead to a relativistic quantum expression for the ponderomotive force and to a new class of ‘hybrid’ emission processes.

scholarly journals Mixed NNLO QCD×electroweak corrections of $$ \mathcal{O} $$(Nfαsα) to single-W/Z production at the LHC

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Stefan Dittmaier ◽  
Timo Schmidt ◽  
Jan Schwarz
Keyword(s):  
Z Bosons ◽  
Leading Order ◽  
Current Standard ◽  
Gauge Invariant ◽  
Mass Distributions ◽  
Self Energy ◽  
Electroweak Gauge Boson ◽  
First Results ◽  
Invariant Part ◽  
The Impact

Abstract First results on the radiative corrections of order $$ \mathcal{O} $$ O (Nfαsα) are presented for the off-shell production of W or Z bosons at the LHC, where Nf is the number of fermion flavours. These corrections comprise all diagrams at $$ \mathcal{O} $$ O (αsα) with closed fermion loops, form a gauge-invariant part of the next-to-next-to-leading-order corrections of mixed QCD×electroweak type, and are the ones that concern the issue of mass renormalization of the W and Z resonances. The occurring irreducible two-loop diagrams, which involve only self-energy insertions, are calculated with current standard techniques, and explicit analytical results on the electroweak gauge-boson self-energies at $$ \mathcal{O} $$ O (αsα) are given. Moreover, the generalization of the complex-mass scheme for a gauge-invariant treatment of the W/Z resonances is described for the order $$ \mathcal{O} $$ O (αsα). While the corrections, which are implemented in the Monte Carlo program Rady, are negligible for observables that are dominated by resonant W/Z bosons, they affect invariant-mass distributions at the level of up to 2% for invariant masses of ≳ 500 GeV and are, thus, phenomenologically relevant. The impact on transverse-momentum distributions is similar, taking into account that leading-order predictions to those distributions underestimate the spectrum.

scholarly journals Classical gravitational self-energy from double copy

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Gabriel Luz Almeida ◽  
Stefano Foffa ◽  
Riccardo Sturani
Keyword(s):  
Gravitational Field ◽  
Binary System ◽  
The Self ◽  
Gravitational Coupling ◽  
Leading Order ◽  
Body System ◽  
Self Energy ◽  
Composite Systems ◽  
Body Dynamics ◽  
Double Copy

Abstract We apply the classical double copy to the calculation of self-energy of composite systems with multipolar coupling to gravitational field, obtaining next-to-leading order results in the gravitational coupling GN by generalizing color to kinematics replacement rules known in literature. When applied to the multipolar description of the two-body system, the self-energy diagrams studied in this work correspond to tail processes, whose physical interpretation is of radiation being emitted by the non-relativistic source, scattered by the curvature generated by the binary system and then re-absorbed by the same source. These processes contribute to the conservative two-body dynamics and the present work represents a decisive step towards the systematic use of double copy within the multipolar post-Minkowskian expansion.

Regge behavior of spontaneously broken non-Abelian gauge theory

1978 ◽  
Vol 17 (2) ◽  
pp. 585-597 ◽  
Author(s):  
J. B. Bronzan ◽  
R. L. Sugar
Keyword(s):  
Gauge Theory ◽  
Abelian Gauge ◽  
Abelian Gauge Theory ◽  
Regge Behavior
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