Proton decay signatures of orbifold GUTs

In grand unified theories based on orbifold constructions in higher dimensions, Higgsino-mediated proton decay is absent. However, proton decay mediated by X and Y gauge bosons is typically enhanced to levels detectable by current and future experiments. We analyse the phenomenology of proton decay induced by the minimal coupling of X,Y gauge bosons. In particular, we show that the novel realization of matter in orbifold GUTs can lead to unusual final state flavour structure, for example, the dominance of the p→K0μ+ mode. Furthermore, we discuss proton decay induced by higher-derivative brane operators, finding potentially observable rates for natural values of the operator coefficients.