Infrared and ultraviolet cutoffs of quantum field theory

Quantum gravity arguments and the entropy bound for effective field theories proposed by Cohen, Kaplan, and Nelson [Phys. Rev. Lett. 82, 4971 (1999)] lead us to consider two correlated scales which parametrize departures from relativistic quantum field theory at low and high energies. A simple estimate of their possible phenomenological implications leads us to identify a scale of around 100 TeV as an upper limit on the domain of validity of a quantum-field-theory description of nature. This fact agrees with recent theoretical developments in large extra dimensions. Phenomenological consequences in the beta-decay spectrum and cosmic-ray physics associated with possible Lorentz invariance violations induced by the infrared scale are discussed. It is also suggested that this scale might produce new unexpected effects at the quantum level.