Non-Abelian Born-Infeld Action and Type I - Heterotic Duality (I): Heterotic F^6 Terms at Two Loops

TL;DR

This paper computes two-loop F^6 interactions in heterotic string theory, revealing results that differ from expected non-Abelian Born-Infeld generalizations and exploring their duality with Type I string interactions.

Contribution

It provides the first detailed two-loop heterotic F^6 effective action calculation and discusses its discrepancy with non-Abelian Born-Infeld theory.

Findings

Two-loop heterotic F^6 interactions are determined up to constants.

Results differ from non-Abelian Born-Infeld expectations.

Discrepancy explained through duality considerations.

Abstract

We study the two-loop F^6 interactions in SO(32) heterotic superstring theory in D=10. By using the generalized Riemann identity we are able to determine the single-trace part of the effective action up to a few constants which are related to certain scattering amplitudes. This two-loop heterotic result is related by duality to Type I interactions at the tree level. However, it turns out to be completely different from any sort of non-Abelian generalization of Born-Infeld theory. We offer an explanation of this discrepancy.