N=1 type IIA brane configurations, chirality and T-duality

We consider four-dimensional N = 1 field theories realized by type IIA bran e configurations of NS-branes and D4-branes, in thr presence of orientifold six-planes and D6-branes. These configurations are known to present intere sting effects associated to the appearance of chiral symmetries and chiral matter in the four-dimensional field theory. We focus on models with one co mpact direction (elliptic models) and show that, under T-duality, the confi gurations are mapped to a set of type IIB D3-branes probing,N = 1 orientifo lds of C-2/Z(N), singularities. We explicitly construct these orientifolds, and show the field theories on the D3-brane probes indeed reproduce the fi eld theories constructed using the IIA brane configurations. This T-duality map allows us to understand the type IIB realization of several exotic bra ne dynamics effects on the type IIA side: Flavor doubling, the splitting of D6-branes and O6-planes in crossing an NS-brane and the effect of a non-ze ro type IIA cosmological constant rum out to have surprisingly standard typ e IIB counterparts. (C) 2000 Elsevier Science B.V. All rights reserved.