Low Energy Consequences of Five Dimensional SO(10)

We consider five dimensional (5D) supersymmetric SO(10) compactified on the orbifold $S^1\mathrm{/}(Z_2\times Z_2^{\mathrm{\prime }})$ such that the SO(10) gauge symmetry is broken on both fixed points (branes), and the residual gauge symmetry is $SU(3{)}_c\times SU(2{)}_L\times U(1{)}_Y\times U(1{)}_X$. We explore one example in which the gauge symmetries on the two branes are respectively $SU(5)\times U(1)_X$and$SU(4)_c\times SU(2)_L\times SU(2)_R$, 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 $U(1{)}_F$ symmetry. Unification of the MSSM gauge couplings and proton stability are also considered. An order of magnitude increase in sensitivity could reveal proton decay.