Infrared singularities of massless gauge theories.
Prof. Lorenzo Magnea (Universita di Torino, Italien)

Abstract: The existence of infrared divergences in gauge theory amplitudes was once described as ′the infrared catastrophe ′. Today, quite to the contrary, we understand that long-distance singularities have important phenomenological consequences, and point to deep properties of non-abelian gauge theories. After a brief general introduction to the subject, I will summarize recent progress in our understanding of infrared divergences to all orders in perturbation theory, and I will point out possible applications, notably to the high-energy limit of QCD cross sections.