On α ′-effects from D -branes in 4 d N $$ \mathcal{N} $$ = 1

In this work we study type IIB Calabi-Yau orientifold compactifications in the presence of space-time filling D7-branes and O7-planes. In particular, we conclude that α′2gs-corrections to their DBI actions lead to a modification of the four-dimensional $$ \mathcal{N} $$ = 1 Kahler potential and coordinates. We focus on the one-modulus case of the geometric background i.e. h1,1 = 1 where we find that the α′2gs-correction is of topological nature. It depends on the first Chern form of the four-cycle of the Calabi-Yau orientifold which is wrapped by the D7-branes and O7-plane. This is in agreement with our previous F-theory analysis and provides further evidence for a potential breaking of the no-scale structure at order α′2gs. Corrected background solutions for the dilaton, the warp-factor as well as the internal space metric are derived. Additionally, we briefly discuss α′-corrections from other Dp-branes.