Type IIB orientifolds on Gepner points

TL;DR

This paper explores orientifold projections of Type IIB string theory on Gepner points, analyzing how moddings affect gauge symmetries, generations, and topology, and constructing non-supersymmetric models with antibranes free of tachyons.

Contribution

It introduces new methods for implementing moddings in Gepner models, leading to diverse gauge and topological features, including non-supersymmetric, tachyon-free configurations.

Findings

Moddings induce reduction in generations and gauge symmetry changes.

Non-supersymmetric models with antibranes and no tachyons are constructed.

Systematic classification of models in D=8, with examples in D=6 and D=4.

Abstract

We study various aspects of orientifold projections of Type IIB closed string theory on Gepner points in different dimensions. The open string sector is introduced, in the usual constructive way, in order to cancel RR charges carried by orientifold planes. Moddings by cyclic permutations of the internal N=2 superconformal blocks as well as by discrete phase symmetries are implemented. Reduction in the number of generations, breaking or enhancements of gauge symmetries and topology changes are shown to be induced by such moddings. Antibranes sector is also considered; in particular we show how non supersymmetric models with antibranes and free of closed and open tachyons do appear in this context. A systematic study of consistent models in D=8 dimensions and some illustrative examples in D=6 and D=4 dimensions are presented.