Tadpole versus anomaly cancellation in D=4,6 compact IIB orientifolds

TL;DR

This paper examines the relationship between tadpole cancellation and gauge anomaly cancellation in D=4,6 Type IIB orientifolds, revealing that tadpole conditions are generally stronger and do not fully determine the gauge group.

Contribution

It clarifies the connection between tadpole and anomaly cancellation and presents new solutions for gauge groups in D=4,6 orientifolds beyond previous literature.

Findings

Tadpole cancellation implies gauge anomaly cancellation but is stronger in D=4, N=1 orientifolds.

Tadpole conditions do not fully fix the gauge group in Z_N D=4,6 orientifolds.

New gauge group solutions are found that differ from earlier reports.

Abstract

It is often stated in the literature concerning D=4,6 compact Type IIB orientifolds that tadpole cancellation conditions i) uniquely fix the gauge group (up to Wilson lines and/or moving of branes) and ii) are equivalent to gauge anomaly cancellation. We study the relationship between tadpole and anomaly cancellation conditions and qualify both statements. In general the tadpole cancellation conditions imply gauge anomaly cancellation but are stronger than the latter conditions in D=4, N=1 orientifolds. We also find that tadpole cancellation conditions in Z_N D=4,6 compact orientifolds do not completely fix the gauge group and we provide new solutions different from those previously reported in the literature.