Split symmetries

Abstract

We consider six-dimensional supergravity with gauge group $SO(10)\times U(1{)}_A$, compactified on the orbifold $T^2/{\mathbb{Z}}_2$. 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.

Comments: 14 pages, 1 figure, clarifying paragraph added, to appear in PLB