TASI Lectures: Particle Physics from Perturbative and Non-perturbative Effects in D-braneworlds

TL;DR

This paper reviews how particle physics models emerge from type II orientifold compactifications, focusing on D-branes, chiral matter, global consistency, and non-perturbative effects like D-instantons, highlighting their role in model building and moduli stabilization.

Contribution

It provides a comprehensive overview of semi-realistic particle physics from D-branes in type II orientifolds, emphasizing global consistency, non-perturbative effects, and the advantages of quiver gauge theories.

Findings

Gauge theories arise on D-branes wrapping cycles in Calabi-Yau.

Chiral matter appears at D-brane intersections, related to topological intersection numbers.

D-instantons can generate superpotential corrections and aid moduli stabilization.

Abstract

In these notes we review aspects of semi-realistic particle physics from the point of view of type II orientifold compactifications. We discuss the appearance of gauge theories on spacetime filling D-branes which wrap non-trivial cycles in the Calabi-Yau. Chiral matter can appear at their intersections, with a natural interpretation of family replication given by the topological intersection number. We discuss global consistency, including tadpole cancellation and the generalized Green-Schwarz mechanism, and also the importance of related global $U(1)$ symmetries for superpotential couplings. We review the basics of D-instantons, which can generate superpotential corrections to charged matter couplings forbidden by the global $U(1)$ symmetries and may play an important role in moduli stabilization. Finally, for the purpose of studying the landscape, we discuss certain advantages of studying quiver gauge theories which arise from type II orientifold compactifications rather than globally defined models. We utilize the type IIa geometric picture and CFT techniques to illustrate the main physical points, though sometimes we supplement the discussion from the type IIb perspective using complex algebraic geometry.