HET seminar: Song He

Speaker: Song He

Title: Scattering Amplitudes from Geometries at Infinity

Abstract: 

Scattering amplitudes play a prominent role not only in high energy particle physics, but also for quantum gravity in asymptotically flat spacetime.The search for a "theory at infinity” of the S-Matrix has revealed surprising geometric structures, and by viewing amplitudes as differential forms we propose a novel geometric picture directly in kinematic space for a wide range of massless theories in general dimensions.

In particular, tree amplitudes of bi-adjoint scalars are given by the “volume” of an associahedron in kinematic space, and scattering equations act as a diffeomorphism from moduli space to it. We find general “scattering forms” dual to color-dressed amplitudes e.g. for gluons and pions; such forms are well-defined in projectivized space, a property which provide a geometric origin for color-kinematics duality.