Leptoquarks in SUSY unified models and the HERA events

Motivated by the recent HERA events which are consistent with a possible leptoquark interpretation, we discuss the prospects for including additional light colour triplets and anti-triplets in the spectrum of supersymmetric unified theories. We focus on a particular string-inspired Pati-Salam model, and propose a simple mechanism by which a light colour triplet of charge −13 plus anti-triplet of charge 13, may have a mass of order 200 GeV, with one of the new states having leptoquark couplings and with proton decay suppressed. We also discuss possible scenarios for gauge unification in such a model.