Half-integer charged hadrons from higher dimensions

Certain embeddings of the low energy SU(3)sub(C) x SU(2)sub(L) x U(1)sub(y) gauge group within the higher dimensional symmetry lead to exotic chiral generations in addition to a number of standard generations. An example is studied, leading to an anomaly free chiral exotic generation consisting of quarks with electric charge +1/6 and -5/6, the corresponding antiquarks and additional integer charged leptons. The most striking prediction from such a compactification would be the existence of stable half-integer charged hadrons with a mass of the order of the Fermi scale. Detection of such particles would be an impressive hint for the existence of more than four dimensions. (orig.)