Discrete Wilson lines in N=1 D=4 type IIB orientifolds:: a systematic exploration for Z6 orientifold

We develop techniques to construct general discrete Wilson lines in four-dimensional N = 1 type IIB orientifolds, their T-dual realization corresponds to branes positioned at the orbifold fixed points. The explicit order two and three Wilson lines along with their tadpole consistency conditions are given for D =4 N = 1 Z(6) type IIB orientifold. The systematic search for all models with general order three Wilson lines leads to a small class of inequivalent models. There are only two inequivalent classes of a potentially phenomenologically interesting model that has: a possible SU(3)(color) x SU(2)(R) x SU(2)(R) x U(1)(B-L) gauge structure, arising from a set of branes located at the Z(6) orbifold fixed point. We calculate the spectrum and Yukawa couplings for this model. On the other hand, introduction of anti-branes allows for models with three families and realistic gauge group assignment, arising from branes located at the Z(3) orbifold fixed points. (C) 2001 Elsevier Science B.V. All rights reserved.