Proton Decay Signatures of Orbifold GUTs

In grand unified theories based on orbifold constructions in higher dimensions, Higgsinomediated 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→ Kμ mode. Furthermore, we discuss proton decay induced by higher-derivative brane operators, finding potentially observable rates for natural values of the operator coefficients.