On Chern-Simons Couplings at order $O(\alpha'^2)$

TL;DR

This paper calculates specific higher-order couplings involving Ramond-Ramond and B-fields on D-branes in type IIB string theory using string scattering amplitudes and T-duality, revealing new four-derivative interactions.

Contribution

It explicitly derives the $O(\alpha'^2)$ couplings of Ramond-Ramond and B-fields on D-branes, advancing understanding of higher-derivative corrections in string theory.

Findings

Derived the $O(\alpha'^2)$ couplings involving RR and B-fields.

Identified four-derivative corrections to D-brane actions.

Used string scattering and T-duality to obtain results.

Abstract

Using the explicit string scattering calculation and the linear T-dual ward identity, we evaluate the string theory disc amplitude of one Ramond-Ramond field $C^{(p+1)}$ and two Neveu-Schwarz B-fields in the presence of a single $D_p$-brane in type $IIB$ string theory. From this amplitude we extract the $O(\alpha'^2)$ (or equivalently four-derivative) part of the $D_p$-brane couplings involving these fields.