On α′-effects from D-branes in 4d $$ \mathcal{N} $$ = 1
On α′-effects from D-branes in 4d $$ \mathcal{N} $$ = 1
A bstract 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 ′ 2 g s -corrections to their DBI actions lead to a modification of the four-dimensional $$ \mathcal{N} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>N</mml:mi> </mml:math> …