Covariant Multiloop Superstring Amplitudes

TL;DR

This paper reviews a super-Poincare invariant pure spinor formalism for superstring multiloop amplitudes, showing finiteness and no corrections to certain terms, aligning with duality conjectures.

Contribution

It introduces a multiloop amplitude prescription that simplifies calculations and confirms key finiteness and non-renormalization properties of superstring theory.

Findings

Massless N-point amplitudes vanish for N<4.

Superstring theory is perturbatively finite.

R^4 terms receive no multiloop corrections.

Abstract

In these proceedings, the multiloop amplitude prescription using the super-Poincare invariant pure spinor formalism for the superstring is reviewed. Unlike the RNS prescription, there is no sum over spin structures and surface terms coming from the boundary of moduli space can be ignored. Massless N-point multiloop amplitudes vanish for N<4, which implies (with two mild assumptions) the perturbative finiteness of superstring theory. And R^4 terms receive no multiloop corrections in agreement with the Type IIB S-duality conjecture of Green and Gutperle.