D-Brane and F-Theory Model Building

We review recent progress in the construction of four-dimensional vacua of Type II string theory and F-theory which yield the Standard Model of particle physics (SM) or extensions thereof. In Type II orientifold compactifications, the SM gauge group and chiral spectrum arise from the open string sector of the theory, namely, from stacks of D-branes. The universal features of the chiral spectrum between various sets of D-branes allow for a general approach to build realistic models, which can be implemented in different setups. We describe the realization of this strategy in Type II Calabi–Yau orientifold compactifications and Rational Conformal Field Theories, discussing the specific model building rules and features of each setting. The same philosophy can be extended to F-theory constructions. These provide new model building possibilities, as they combine the localization properties of D-branes with exceptional gauge groups and their representations.