Gauge and gravitational anomalies in D=4 N=1 orientifolds

TL;DR

This paper investigates how gauge and gravitational anomalies are canceled in four-dimensional N=1 orientifold models using a Green-Schwarz mechanism involving twisted Ramond-Ramond fields, with detailed string theory analysis.

Contribution

It provides a detailed string theory analysis confirming anomaly cancellation via twisted Ramond-Ramond fields in D=4 N=1 orientifolds, including explicit couplings and inflow mechanisms.

Findings

Anomalies are canceled by a Green-Schwarz mechanism involving twisted fields.

Explicit couplings of D-branes, O-planes, and fixed points to twisted fields are derived.

Twisted sectors with fixed-planes contribute uniquely to anomaly inflow.

Abstract

The cancellation of U(1)-gauge and U(1)-gravitational anomalies in certain D=4 N=1 Type IIB orientifolds is analyzed in detail, from a string theory point of view. We verify the proposal that these anomalies are cancelled by a Green-Schwarz mechanism involving only twisted Ramond-Ramond fields. By factorizing one-loop partition functions, we also get the anomalous couplings of D-branes, O-planes and orbifold fixed-points to these twisted fields. Twisted sectors with fixed-planes participate to the inflow mechanism in a peculiar way.