Testing orbifold models of Supersymmetric Grand Unification

In a model of supersymmetric SU(5) Grand Unification with a spatial dimension described by the orbifold $S^1/(Z_2 \times Z_2')$, proton decay is naturally suppressed at all orders. This is achieved by a suitable implementation of the discrete symmetries on the brane. But baryon number violating interactions are present in this model. We propose a few possible experimental tests of this model which exploit the effect of the baryon number violating couplings on low-energy observables like neutron-antineutron oscillations, double nucleon decay into two kaons, hadronic decay widths of the $Z$ boson, and $t \bar t$ production cross-section in Run II of the Tevatron.