High Energy Theory Seminar

The central drive of the analytic S-matrix program is to determine scattering amplitudes in any given theory from symmetries and analytic properties. This program led for instance to the birth of string theory with Veneziano's amplitude. Many recent developments in four dimensional field theory are closely related to this program. Here one of these, the notion of (linearized) on-shell superspace, will be extended to higher dimensions. Two main examples of the uses of these spaces will be presented in superstring theory in a flat background. First all three point amplitudes with one massive and two massless legs in the open superstring will be determined up to a normalization. Second a series of amplitudes in type IIB will be uncovered which in a precise sense violate R-symmetry maximally. These are a direct analog of four dimensional "MHV" amplitudes. Both examples display remarkable simplicity.