Description:

The study of scattering amplitudes as on-shell functions of kinematic variables can teach us a lot about quantum field theories. At tree-level, a lot is known about the singularities of these rational functions that stem from their denominators, all of which are consequences of locality, unitarity and causality. What is known about numerators?

Typically, the zeros of an amplitude are related to symmetries (often spontaneously broken ones) of the corresponding quantum field theory, just as its locality is known to give rise to poles. Recently, Arkani-Hamed et al. discovered the presence of a broader set of hidden zeros in amplitudes of a specific set of colored quantum field theories (a special example is the radiation zero in W-scattering). They also noticed that the theories factorize at these special kinematic points. In this presentation, we will see that these theories satisfy the BCJ relations. We also study how the zeros interact with higher-derivative corrections and the double copy map, a way to build permutation-invariant amplitudes from ordered ones.

Shruti Parajape, Chancellor's Postdoctoral Fellow, University of California-Davis

Host: JJ Carrasco