HET Journal club: Carlos Cardona

Abstract: We explore the correspondence between four-dimensional flat space S-matrix and two-dimensional CFT. We demonstrate that the factorization singularities of an n-point cubic diagram reproduces AdS Witten diagrams if mass conservation is imposed. Such configuration arises naturally if we consider the 4-dimensional S-matrix as a compactified massless 5-dimensional theory. This identification allows us to rewrite the massless S-matrix in the CHY formulation, where the factorization singularities are re-interpreted as factorization limits of a Riemann sphere and the map is recast into a form of 2d/2d correspondence.