Three generations in type I compactifications - art. no. 126001

Generalizing the recent work on three-family type I compactifications, we c lassify perturbative type I vacua obtained via compactifying on the T-6/Z(2 )xZ(2)xZ(3) orbifold with all possible Wilson lines. In particular, we conc entrate on models with gauge groups containing the standard model gauge gro up SU(3)(c)x SU(2),(w)x U(1)(Y) as a subgroup. All of the vacua we obtain c ontain D5-branes and are nonperturbative from the heterotic viewpoint. The models we discuss have three chiral families. We study some of their phenom enological properties, and point out nontrivial problems arising in these m odels in the phenomenological context. [S0556-2821 (98)02424-2].