Anomalous D-brane and orientifold couplings from the boundary state

TL;DR

This paper calculates scattering amplitudes involving R-R and NS-NS fields to provide evidence for anomalous couplings in D-branes and orientifold planes, confirming their theoretical predictions.

Contribution

It offers direct amplitude-based evidence for anomalous couplings in D-brane and orientifold actions, especially regarding Pontrjagin class interactions.

Findings

D9-brane and O9-plane couple to the first Pontrjagin class as expected

Provides direct amplitude evidence for anomalous couplings

Confirms the relative strength of these couplings

Abstract

We compute scattering amplitudes involving both R-R and NS-NS fields in the presence of a D-brane or orientifold plane. These provide direct evidence for the anomalous couplings in the D-brane and orientifold actions. The D9-brane and O9-plane are found to couple to the first Pontrjagin class with the expected relative strength.