Theory HEP Seminar

Recent progress on long-distance singularities in QCD amplitudes

Einan Gardi

University of Edinburgh

I will review the state-of-the-art understanding of long-distance singularities in QCD amplitudes. After recalling the general properties of long-distance singularities in multi-leg scattering amplitude, I will focus on the structure of the soft anomalous dimension which was determined a couple of years ago to three-loop order. I will then describe an alternative derivation of its functional form using a bootstrap technique, illustrating the complementarity between the study of long-distance singularities and that of amplitudes in special kinematic limits, such as the high-energy limit and collinear limits.