# The different faces of branes in Double Field Theory

## TL;DR

This paper embeds the Wess-Zumino terms of various string theory branes into double field theory, revealing how T-duality affects brane faces and their interactions, including in massive backgrounds.

## Contribution

It introduces a framework for understanding brane Wess-Zumino terms within double field theory, accounting for T-duality, mass parameters, and exotic branes.

## Key findings

- Branes exhibit different faces under T-duality depending on their worldvolume and transverse directions.
- Wess-Zumino terms are modified in backgrounds with non-zero Romans mass.
- Brane creation processes involve exotic branes when passing through each other in massive backgrounds.

## Abstract

We show how the Wess-Zumino terms of the different branes in string theory can be embedded within double field theory. Crucial ingredients in our construction are the identification of the correct brane charge tensors and the use of the double field theory potentials that arise from dualizing the standard double field theory fields. This leads to a picture where under T-duality the brane does not change its worldvolume directions but where, instead, it shows different faces depending on whether some of the worldvolume and/or transverse directions invade the winding space. As a non-trivial by-product we show how the different Wess-Zumino terms are modified when the brane propagates in a background with a non-zero Romans mass parameter. Furthermore, we show that for non-zero mass parameter the brane creation process, when one brane passes through another brane, gets generalized to brane configurations that involve exotic branes as well.