Infrared singularities in multi-leg scattering amplitudes

Understand

I discuss the state-of-the-art knowledge of long-distance singularities in multi-leg gauge-theory scattering amplitudes and report on an on-going calculation of the three-loop soft anomalous dimension through the renormalization of correlators of semi-infinite Wilson lines.

• I also discuss the non-Abelian exponentiation theorem that has been recently generalised to multiple Wilson lines and demonstrate its application in computing the soft anomalous dimension.
• Finally, I present recent results for multiple-gluon-exchange webs and discuss their analytic structure.