Four-Derivative Brane Couplings from String Amplitudes

TL;DR

This paper derives four-derivative couplings involving Ramond-Ramond and B-fields on Dp-branes from string amplitude calculations, ensuring gauge invariance and T-duality consistency.

Contribution

It provides the explicit form of higher-derivative couplings on Dp-branes from string amplitudes, extending the understanding of brane effective actions.

Findings

Derived four-derivative couplings from string amplitudes

Couplings are gauge invariant under R-R and NS-NS transformations

Results are consistent with linear T-duality

Abstract

We evaluate the string theory disc amplitude of one Ramond-Ramond field C^(p-3) and two Neveu-Schwarz B-fields in the presence of a single Dp-brane in type II string theory. From this amplitude we extract the four-derivative (or equivalently order (alpha')^2) part of the Dp-brane action involving these fields. We show that the new couplings are invariant under R-R and NS-NS gauge transformations and compatible with linear T-duality.