Branes, Orientifolds and Chiral Gauge Theories

TL;DR

This paper explores the behavior of branes and orientifolds in string theory, revealing how orientifolds can form bound states at strong coupling and analyzing the moduli space of certain supersymmetric gauge theories with brane methods.

Contribution

It introduces new insights into the strong coupling dynamics of orientifolds and provides a detailed analysis of the moduli space of N=2 and N=1 supersymmetric gauge theories using brane configurations.

Findings

Orientifolds can become bound states with branes at strong coupling.

Sign flip of orientifold planes explained via worldsheet arguments.

Moduli space of N=2 theories with symplectic and orthogonal groups characterized.

Abstract

We discuss some aspects of the physics of branes in the presence of orientifolds and the corresponding worldvolume gauge dynamics. We show that at strong coupling orientifolds sometimes turn into bound states of orientifolds and branes, and give a worldsheet argument for the flip of the sign of an orientifold plane split into two disconnected parts by an NS fivebrane. We also describe the moduli space of vacua of N=2 supersymmetric gauge theories with symplectic and orthogonal gauge groups, and analyze a set of four dimensional N=1 supersymmetric gauge theories with chiral matter content using branes.