Orientifolds of SU(2)/U(1) WZW Models

The orientifolds of SU(2)/U(1) gauged WZW models are investigated. In particular, we construct the new type orientifolds and identify their geometries. We closely follow the analysis of D-branes in the SU(2)/U(1) WZW models, which was given by Maldacena, Moore and Seiberg.Comment: 33 pages, 3 figures, the geometry of orientifolds corrected and the spectral flow identification reconsidere