Anomaly Cancellation On Manifolds Of G_2 Holonomy

TL;DR

This paper explores how anomaly cancellation occurs in singular G_2 manifolds used in M-theory compactifications, highlighting the role of anomaly inflow and comparing predictions with explicit models.

Contribution

It provides a detailed mechanism for anomaly cancellation in singular G_2 manifolds, connecting bulk inflow with gauge group and matter content.

Findings

Anomaly cancellation depends on inflow from the bulk.

Singular G_2-manifolds can produce nonabelian gauge groups with chiral fermions.

Comparison with explicit models supports the proposed anomaly cancellation mechanism.

Abstract

Smooth manifolds of G_2 holonomy, used to compactify M-theory to four dimensions, give only abelian gauge groups without charged matter multiplets. But singular G_2-manifolds can give abelian or nonabelian gauge groups with chiral fermions. We describe the mechanism of anomaly cancellation in these models, which depends upon anomaly inflow from the bulk. We also compare the anomaly predictions to what has been learned by more explicit arguments in some special cases.