R^4 Corrections and Flux Superpotential in Heterotic M-theory

I will describe two kinds of corrections to the previously known effective action of heterotic M-theory. The first is due to taking into account the 11d R^4 term. This results in a new contribution to the Kahler potential of the four-dimensional effective theory. The second comes from the flux-generated superpotential. To derive systematically the form of this superpotential, one has to use the approach of group structures. It is essential to consider SU(3), not G_2, structure on the internal 7d manifold. Finally, I will address the issue of how these corrections affect the existence of dS vacua in heterotic M-theory, which were originally found by balancing open membrane instanton effects and gaugino condensation.