Towards the double copy formulation for the Abelian sector of heterotic double field theory

It is known that the double field theory (DFT) action can be constructed perturbatively up to cubic order through the double copy of the Yang–Mills (YM) theory. This approach also extends to higher-derivative YM theories, yielding higher-derivative DFT actions. In this work, we generalize this classical double copy framework to the Abelian subsector of the heterotic DFT. Specifically, we start from a YM theory coupled to a charged scalar field, namely the "YM+ " theory. Applying the double copy procedure, we obtain an action that precisely reproduces the Abelian sector of the heterotic DFT up to cubic order.