The generalized Green-Schwarz mechanism for type IIB orientifolds with D3-and D7-branes

In this paper, we work out in detail the tadpole cancellation conditions as well as the generalized Green-Schwarz mechanism for type IIB orientifold compactifications on smooth Calabi-Yau three-folds with D3- and D7-branes. We find that not only the D3- and D7-tadpole conditions have to be satisfied, but in general also the vanishing of the induced D5-brane charges leads to a non-trivial constraint. In fact, for the case h_(1, 1) not equal 0 the latter condition is important for the cancellation of chiral anomalies. We also extend our analysis by including D9- as well as D5-branes and determine the rules for computing the chiral spectrum of the combined system.