Split symmetries

We consider six-dimensional supergravity with gauge group SO(10)×U(1)A , compactified on the orbifold T2/Z2 . Three quark-lepton generations arise as zero modes of a bulk 16 -plet due to magnetic flux of the anomalous U(1)A . Boundary conditions at the four fixed points break SO(10) to subgroups whose intersection is the Standard Model gauge group. The gauge and Higgs sector consist of “split” SO(10) multiplets. As consequence of the U(1)A flux, squarks and sleptons are much heavier than gauge bosons, Higgs bosons, gauginos and higgsinos. We thus obtain a picture similar to “split supersymmetry”. The flavor structure of the quark and lepton mass matrices is determined by the symmetry breaking at the orbifold fixed points