Split extended supersymmetry from intersecting branes

We study string realizations of split extended supersymmetry, recently proposed in [I. Antoniadis, et al. hep-ph/0507192]. Supersymmetry is broken by small (ϵ) deformations of intersection angles of D-branes giving tree-level masses of order m02∼ϵMs2, where MsMs is the string scale, to localized scalars. We show through an explicit one-loop string amplitude computation that gauginos acquire hierarchically smaller Dirac masses m1/2D∼m02/Ms. We also evaluate the one-loop higgsino mass, μ  , and show that, in the absence of tree-level contributions, it behaves as μ∼m04/Ms3. Finally we discuss an alternative suppression of scales using large extra dimensions. The latter is illustrated, for the case where the gauge bosons appear in N=4N=4 representations, by an explicit string model with Standard Model gauge group, three generations of quarks and leptons and gauge coupling unification.