ELECTROMAGNETIC INTERACTIONS — Workshop L

The Standard Theory

10.1093/oso/9780198805175.003.0006 ◽

2017 ◽

Author(s):

John Iliopoulos

Keyword(s):

Gauge Theory ◽

Invariant Theory ◽

Standard Theory ◽

Strong Interactions ◽

Gauge Invariant ◽

Electromagnetic Interactions ◽

Protons And Neutrons ◽

Free Particles ◽

Theoretical Predictions ◽

Theory And Experiment

All ingredients of the previous chapters are combined in order to build a gauge invariant theory of the interactions among the elementary particles. We start with a unified model of the weak and the electromagnetic interactions. The gauge symmetry is spontaneously broken through the BEH mechanism and we identify the resulting BEH boson. Then we describe the theory known as quantum chromodynamics (QCD), a gauge theory of the strong interactions. We present the property of confinement which explains why the quarks and the gluons cannot be extracted out of the protons and neutrons to form free particles. The last section contains a comparison of the theoretical predictions based on this theory with the experimental results. The agreement between theory and experiment is spectacular.

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Soft photon theorem in the small negative cosmological constant limit

Journal of High Energy Physics ◽

10.1007/jhep08(2021)105 ◽

2021 ◽

Vol 2021 (8) ◽

Author(s):

Nabamita Banerjee ◽

Karan Fernandes ◽

Arpita Mitra

Keyword(s):

Cosmological Constant ◽

Tree Level ◽

Leading Order ◽

Asymptotically Flat ◽

Soft Factor ◽

Flat Spacetime ◽

Electromagnetic Interactions ◽

Flat Spacetimes ◽

Perturbative Corrections ◽

Soft Factors

Abstract We study the effect of electromagnetic interactions on the classical soft theorems on an asymptotically AdS background in 4 spacetime dimensions, in the limit of a small cosmological constant or equivalently a large AdS radius l. This identifies 1/l2 perturbative corrections to the known asymptotically flat spacetime leading and subleading soft factors. Our analysis is only valid to leading order in 1/l2. The leading soft factor can be expected to be universal and holds beyond tree level. This allows us to derive a 1/l2 corrected Ward identity, following the known equivalence between large gauge Ward identities and soft theorems in asymptotically flat spacetimes.

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