Complete N-Point Superstring Disk Amplitude I. Pure Spinor Computation

Understand

In this paper the pure spinor formalism is used to obtain a compact expression for the superstring N-point disk amplitude.

• The color ordered string amplitude is given by a sum over (N-3)! super Yang-Mills subamplitudes multiplied by multiple Gaussian hypergeometric functions.
• In order to obtain this result, the cohomology structure of the pure spinor superspace is exploited to generalize the Berends-Giele method of computing super Yang-Mills amplitudes.
• The method was briefly presented in [1], and this paper elaborates on the details and contains higher-rank examples of building blocks and associated cohomology objects.