Baryon-number violation at accelerator energies

We study an SU5 grand unified model with a stable proton. Proton stability is ensured by requiring that all interactions conserve a global quantum number called "chromality" and that the proton be the lightest particle to have 0. Minimally implemented, these ideas require a doubling of fermions (conveniently labeled "standard" and "exotic") in each family and the introduction of a 5 and 45 of Higgs fields. The model may then have a relatively light color-triplet Higgs field h±, which can mediate the baryon-number-nonconserving decays of exotic fermions to the standard ones. We examine the phenomenology of the model and put bounds on the masses of the particles it postulates. In particular, we find that a color triplet h± of mass mh102mW is consistent with all the low-energy data currently available. This gives rise to the logical possibility of observing baryon-number-nonconserving events at accelerators, provided that the exotic fermions are light enough to be produced there. We study the production and decay of exotic fermions in planned e+e- and p»p facilities. We find that if they exist in the relevant mass range they could be produced in sufficient numbers (typically 103-104 exotic pairs per day at CERN LEP, the Stanford Linear Collider and Fermilab Tevatron I, and 10/day at the CERN SPS) for the phenomenon of baryon-number violation to be observed. Other signatures include the decay of the exotic fermions a macroscopic distance from the production vertex and the presence of two high-energy charged leptons of the same sign among the decay products.