The Kinoshita–Lee–Nauenberg theorem or KLN theorem states that perturbatively the
standard model
The Standard Model of particle physics is the Scientific theory, theory describing three of the four known fundamental forces (electromagnetism, electromagnetic, weak interaction, weak and strong interactions – excluding gravity) in the unive ...
as a whole is infrared (IR) finite. That is, the
infrared divergences coming from loop integrals are canceled by IR divergences coming from
phase space
The phase space of a physical system is the set of all possible physical states of the system when described by a given parameterization. Each possible state corresponds uniquely to a point in the phase space. For mechanical systems, the p ...
integrals. It was introduced independently by and .
An analogous result for
quantum electrodynamics
In particle physics, quantum electrodynamics (QED) is the Theory of relativity, relativistic quantum field theory of electrodynamics. In essence, it describes how light and matter interact and is the first theory where full agreement between quant ...
alone is known as Bloch–Nordsieck theorem.
Ultraviolet divergences in perturbative
quantum field theory
In theoretical physics, quantum field theory (QFT) is a theoretical framework that combines Field theory (physics), field theory and the principle of relativity with ideas behind quantum mechanics. QFT is used in particle physics to construct phy ...
are dealt with in
renormalization
Renormalization is a collection of techniques in quantum field theory, statistical field theory, and the theory of self-similar geometric structures, that is used to treat infinities arising in calculated quantities by altering values of the ...
.
References
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*Taizo Muta, Foundations of Quantum Chromodynamics: An Introduction to Perturbative Methods in Gauge Theories, World Scientific Publishing Company; 3 edition (September 30, 2009)
Standard Model
Quantum field theory
Theorems in quantum mechanics
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