Abstract

I will present the open string tree level amplitude of massless states to any number of external legs. It turns out that the kinematic factor of disk amplitudes is entirely captured by the underlying SYM field theory, i.e. that all the dependence on polarization vectors enters through color ordered SYM amplitudes. Moreover, the structure of the N point string theory amplitude exploits the minimal basis of (N-3)! SYM subamplitudes and adjoins a dual basis of (N-3)! hypergeometric functions encoding the alpha’ corrections. These patterns within disk amplitudes exhibit rich implications from and to field theory.The pure spinor formalism is the crucial tool to identify SYM amplitudes within the string computation. That is why I introduce a compact representation for N point SYM amplitudes in pure spinor superspace. It reflects the decomposition into cubic diagrams a la Bern, Carrasco, Johansson and generalizes Berends Giele recursion relations.