Twisted Orientifold planes and S-duality without supersymmetry

TL;DR

This paper introduces a non-supersymmetric orientifold of type IIB string theory, realized via a Scherk-Schwarz deformation, with stable D-branes and twisted O-planes, and explores its F-theory and M-theory interpretations.

Contribution

It constructs a novel non-supersymmetric orientifold with twisted O-planes and demonstrates its realization in F-theory and M-theory frameworks.

Findings

Stable D-branes match M-theory predictions.

The theory exhibits SL(2,Z) self-duality.

Twisted O-planes couple only to massive states.

Abstract

We construct a novel orientifold of type IIB string theory that breaks all supersymmetries. It is a closed string theory without open sector and it can be understood as a Scherk-Schwarz deformation in which supersymmetry is restored at infinite radius. We conjecture that it is realised in F-theory as a compactification on a freely acting orbifold that acts as the reflection on the elliptic fibre. The SL(2,Z) selfduality is manifest in the F-theory formulation. We construct explicitly the D-branes in this model and find that stable D-branes match the geometric prediction in M-theory. This theory has the salient feature that the O-planes couple only to the massive twisted states of the theory. We call them twisted O-planes. We describe supersymmetric examples of such twisted O-planes and argue that they are similar in nature to combinations of O+ and O- planes with vanishing total charge.