Imaginary parts and discontinuities of Wilson line correlators
Mercredi 01/10/2014, 14:15
Salle Claude Itzykson, Bât. 774, Orme des Merisiers
The infrared singularities of gauge theory scattering amplitudes play a fundamental role in particle physics. A key tool for computing such infrared singularities is provided by correlators of straight semi-infinite Wilson lines. In this talk I introduce a notion of position-space cuts of eikonal diagrams, as a method to compute the imaginary part of Wilson line correlators. I compare our position-space cuts to the standard momentum-space Cutkosky cutting rules, and discuss the origin of the imaginary part from the point of view of causality as well as unitarity. In the end I demonstrate the application of our formalism to several two- and three-loop eikonal diagrams.