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Theoretical Physics II

Special seminar "On-shell recursion relations for electroweak scattering amplitudes"

11/03/2017

By Robert Franken, RWTH Aachen, Institut für Theoretische Teilchenphysik und Kosmologie

Abstract:

This master thesis recapitulates the spinor helicity formalism for the massive particle content of the standard model. The massive spinor helicity formalism is subsequently used to deform the momenta of an arbitrary number of massive external particles in a manner developed by Britto, Cachazo, Feng and Witten for two, by Risager for three and by Cheung, Shen and Trnka for an arbitrary number of massless particles. This leads to recursion relations for scattering amplitudes containing external or internal massive particles to construct these amplitude out of a set of seed amplitudes with a lower number of external particles. This thesis shows that the massive standard model is completely constructible under a deformation of at most five external momenta (in contrast to three in the massless case) and provides a broad class of amplitudes that are constructible under a deformation of three momenta. It furthermore shows that the seed amplitudes needed for the recursion are only the fundamental interaction amplitudes that can be read off from the Lagrangian. With these seed amplitudes the selection rules for massive vector boson scattering amplitudes are succinctly derived.

Friday, 3 November 2017
Time: 2:15 pm
Room: SE 22.00.017, Hubland Nord

 

 

By Ansgar Denner

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