Towards mass deformed N = 4 SO(n) and Sp(k) theories from brane configurations Original Research Article

We study the introduction of orientifold 6-planes in the type IIA brane configurations known as elliptic models. The N = 4 SO(n) and Sp(k) theories softly broken to N = 2 through a mass for the adjoint hypermultiplet can be realized in this framework in the presence of two orientifold planes with opposite RR charge. A large class of β = 0 models is solved for vanishing sum of hypermultiplet masses by embedding the type IIA configuration into M-theory. We also find a geometric interpretation of Montonen-Olive duality based on the properties of the curves. We make a proposal for the introduction of non-vanishing sum of hypermultiplet masses in a sub-class of models.