Low energy consequences of five-dimensional <f>SO(10)</f>

We consider five-dimensional (5D) supersymmetric <f>SO(10)</f> compactified on the orbifold <f>S1/(Z2×Z2′)</f> such that the <f>SO(10)</f> gauge symmetry is broken on both fixed points (branes), and the residual gauge symmetry is <f>SU(3)c×SU(2)L×U(1)Y×U(1)X</f>. We explore one example in which the gauge symmetries on the two branes are, respectively, <f>SU(5)×U(1)X</f> and <f>SU(4)c×SU(2)L×SU(2)R</f>, and the MSSM gauge symmetry is recovered by the usual Higgs mechanism. We discuss how fermion masses and mixings can be understood in this framework by introducing a flavor <f>U(1)F</f> symmetry. Unification of the MSSM gauge couplings and proton stability are also considered. An order of magnitude increase in sensitivity could reveal proton decay. [Copyright &y& Elsevier]