The existence of a new fundamental scale may lead to modified dispersion
relations for particles at high energies. Such modifications seem to be
realized with the Planck scale in certain descriptions of quantum gravity. We
apply effective field theory to this problem and identify dimension 5 operators
that would lead to cubic modifications of dispersion relations for Standard
Model particles. We also discuss other issues related to this approach
including various experimental bounds on the strength of these interactions.
Further we sketch a scenario where mixing of these operators with dimensions 3
and 4 due to quantum effects is minimal.Comment: QTS3 proceedings; review of hep-ph/0301124 plus extended discussio