A simpler prescription for MHV graviton tree amplitudes in superstring theory

TL;DR

This paper extends a known superstring amplitude prescription from open to closed strings, demonstrating its consistency with supergravity results and verifying its accuracy for four-graviton MHV amplitudes including string corrections.

Contribution

It introduces a simplified prescription for MHV graviton amplitudes in superstring theory, connecting superstring results with supergravity in the low-energy limit.

Findings

The prescription reduces to supergravity results at  limit.

It correctly computes 4-graviton MHV amplitudes with  corrections.

The method simplifies calculations of superstring MHV amplitudes.

Abstract

We extend the Berkovits-Maldacena prescription for MHV amplitudes of the open superstring to the closed superstring, showing that in the \alpha'=0 limit it reduces to the result of supergravity found recently by Hodges. We also verify that this prescription calculates the correct superstring tree level MHV amplitude for 4 gravitons including \alpha' corrections.