Split extended supersymmetry from intersecting branes

We study string realizations of split extended supersymmetry, recently proposed in hep-ph/0507192. Supersymmetry is broken by small (ǫ) deformations of intersection angles of D-branes giving tree-level masses of order m0 ∼ ǫM2 s , where Ms is the string scale, to localized scalars. We show through an explicit one-loop string amplitude computation that gauginos acquire hierarchically smaller Dirac masses m1/2 ∼ m0/Ms. We also evaluate the one-loop Higgsino mass, μ, and show that, in the absence of tree-level contributions, it behaves as μ ∼ m0/M s . 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 = 4 representations, by an explicit string model with Standard Model gauge group, three generations of quarks and leptons and gauge coupling unification. ∗On leave of absence from CPHT, Ecole Polytechnique, UMR du CNRS 7644