Journal ArticleDOI
Degenerate Systems and Mass Singularities
T. D. Lee,Michael Nauenberg +1 more
TLDR
In this paper, it was shown that under certain general conditions such singularities do not appear in the power series expansions of the transition probabilities, provided these are averaged over an appropriate ensemble of degenerate states.Abstract:
For a system with degenerate energies, the power series expansions of the $S$-matrix elements may become singular. An elementary theorem in quantum mechanics is proved which shows that under certain general conditions such singularities do not appear in the power series expansions of the transition probabilities, provided these are averaged over an appropriate ensemble of degenerate states. Application of this theorem leads to the cancellations of mass singularities and infrared divergences in quantum electrodynamics. The question of whether a charged particle can have zero mass is studied.read more
Citations
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Journal ArticleDOI
Supersymmetric Dark Matter
TL;DR: In this article, the neutralino is considered as a superpartner in many supersymmetric theories, and the cosmological abundance of neutralino and the event rates for both direct and indirect detection schemes are discussed.
Journal ArticleDOI
Supersymmetric Dark Matter
TL;DR: In this article, the neutralino is proposed as the lightest superpartner in many supersymmetric theories, and it is shown how to calculate the cosmological abundance of neutralino and event rates for both direct and indirect detection schemes.
Journal ArticleDOI
Iteration of planar amplitudes in maximally supersymmetric Yang-Mills theory at three loops and beyond
TL;DR: In this paper, the leading-color (planar) three-loop four-point amplitude of N = 4 supersymmetric Yang-Mills theory in 4 - 2 -epsilon dimensions was constructed via the unitarity method, in terms of two Feynman loop integrals, one of which has been evaluated already.
Book
Foundations of Perturbative QCD
TL;DR: In this article, a systematic treatment of perturbative QCD is given, giving an accurate account of the concepts, theorems and their justification, giving strong motivations for the methods.
Journal ArticleDOI
Towards a complete theory of thermal leptogenesis in the SM and MSSM
TL;DR: In this article, a thorough study of thermal leptogenesis was performed by adding finite temperature effects, RGE corrections, scatterings involving gauge bosons and by properly avoiding overcounting on-shell processes.