Orientifolds with discrete torsion
Abstract
We show how discrete torsion can be implemented in D = 4, Script N = 1 typeIIB orientifolds. Some consistency conditions are found from the closed string and open string spectrum and from tadpole cancellation. Only real values of the discrete torsion parameter are allowed, i.e. epsilon = +/1. Orientifold models are related to real projective representations. In a similar way as complex projective representations are classified by H^{2}(Γ,Bbb C*) = H^{2}(Γ,U(1)), real projective representations are characterized by H^{2}(Γ,Bbb R*) = H^{2}(Γ,Bbb Z_{2}). Four different types of orientifold constructions are possible. We classify these models and give the spectrum and the tadpole cancellation conditions explicitely.
 Publication:

Journal of High Energy Physics
 Pub Date:
 July 2000
 DOI:
 10.1088/11266708/2000/07/040
 arXiv:
 arXiv:hepth/0002103
 Bibcode:
 2000JHEP...07..040K
 Keywords:

 High Energy Physics  Theory
 EPrint:
 Latex, 48 pages, v2: several misprints and sign errors corrected, clarifications and references added