Kappa-Symmetry, Supersymmetry and Intersecting Branes

TL;DR

This paper introduces a novel form of κ-symmetry for D-branes, expressing the BI-field dependence as a relative rotation via Γ = e^{-a/2}\, Γ' e^{a/2}, and uses it to systematically determine the amount of supersymmetry preserved by intersecting D- and M-brane configurations at arbitrary angles with constant Born-Infeld fields. The authors develop a unified projection-based framework to count preserved supersymmetry, extend the method to M-branes, and discuss consistency with supergravity backgrounds and covariant quantization. The results reproduce known SUSY fractions for standard intersections and provide a structured approach for configurations with BI fields, highlighting the role of left-right field rotations in preserving or breaking SUSY. Together, these insights advance the understanding of how brane intersections and worldvolume fluxes influence supersymmetry in string/M-theory and its supergravity realizations.

Abstract

We present a new form of kappa-symmetry transformations for D-branes in which the dependence on the Born-Infeld field strength is expressed as a relative rotation on the left- and right-moving fields with opposite parameters. Then, we apply this result to investigate the supersymmetry preserved by certain intersecting brane configurations at arbitrary angles and with non-vanishing constant Born-Infeld fields. We also comment on the covariant quantization of the D-brane actions.