Gravitational Couplings, Orientifolds and M-Planes

TL;DR

This paper investigates the gravitational couplings on various string-theory orientifold planes, analyzing their consistency through dualities and charge transitions, especially focusing on orientifold 3-planes crossing 5-branes.

Contribution

It provides a detailed derivation of gravitational Chern-Simons couplings on orientifold planes and explores their behavior under dualities and charge jumps.

Findings

Derived gravitational couplings for different orientifold planes.

Confirmed consistency of couplings via duality checks.

Identified charge and coupling changes during orientifold 3-plane and 5-brane interactions.

Abstract

We examine string-theory orientifold planes of various types including the Sp and SO-odd planes, and deduce the gravitational Chern-Simons couplings on their world-volumes. Consistency checks are carried out in different spacetime dimensions using various dualities, including those relating string theory with F-theory and M-theory. It is shown that when an orientifold 3-plane crosses a 5-brane, the jump in the charge is accompanied by a corresponding change in the gravitational couplings.