Viktor Svensson
Light like Wilson lines at netxt-to-next-to- leading order


In this thesis, we consider basic properties of Wilson lines, with special attention devoted to the renormalization and exponentiation property. We describe the generationg function approach to non-abelian exponentiation and perform the calculation of the correlator of two and three semi-infinite Wilson lines meeting at a single point to two-loop order. We consider Wilson lines on lightcone and regularize infrared divergences with a delta-regulator. The three line calculation is done within the generating function approach. Using this calculation, we derive the cusp anomalous dimension and soft anomalous dimension at two-loop order. We discuss the problems arising from the use of the delta regulator for lightlike Wilson lines, and conclude that this regularization is inappropriate for higher loop calculation. The obtained result is to be used for higher order analysis of the soft factor and can be used for application inmulti-hadron factorization theorems, threshold resummation, etc.

LU TP 15-23