Unified theories of strong, weak and electromagnetic interactions which have
electric charge quantization predict the existence of topologically stable
magnetic monopoles. Intermediate scale monopoles are comparable with detection
energies of cosmic ray monopoles at IceCube and other cosmic ray experiments.
Magnetic monopoles in some models can be significantly lighter and carry two,
three or possibly even higher quanta of the Dirac magnetic charge. They could
be light enough for their effects to be detected at the LHC either directly or
indirectly. An example based on a D-brane inspired SU(3)CβΓSU(3)LβΓSU(3)Rβ (trinification) model with the monopole carrying three quanta of Dirac
magnetic charge is presented. These theories also predict the existence of
color singlet states with fractional electric charge which may be accessible at
the LHC.Comment: 18 pages, 2 figures, minor revisions, references adde