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TH String Theory Seminar
Yangian invariants, on-shell graphs and deformations
4-3-006 - TH Conference Room (CERN)
4-3-006 - TH Conference Room
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On-shell graphs are a convenient way of representing Yangian invariants which serve as building blocks for amplitudes in N=4 super-Yang-Mills theory. Maintaining Yangian invariance, one can deform these on-shell graphs by shifting the helicities of the external legs. In the first part of the talk, I will discuss the construction of deformed on-shell graphs as well as their relation to scattering amplitudes and the BCFW recursion relation. In addition, I will comment on the possibility of using the deformation parameter as a regulator for the one-loop four-point amplitude. In a second part, I am going to review an algebraic formulation of scattering amplitudes recently suggested by Chicherin, Derkachov and Kirschner. In this language, (deformed) amplitudes are generated by repeatedly acting with certain R-operators on a vacuum and Yangian invariance is ensured by demanding the resulting objects to be eigenstates of a monodromy matrix. I will discuss advantages and extensions of this formalism, relate it to the previous one and will show that the constraints on possible deformations of scattering amplitudes are equivalent.