Effective particles in quantum field theory
  The concept of effective particles is introduced in the Minkowski space-time Hamiltonians in quantum field theory using a new kind of the relativistic renormalization group procedure that does not integrate out high-energy modes but instead integrates out the large changes of invariant mass. The new procedure is explained using examples of known interactions. Some applications in phenomenology, including processes measurable in colliders, are briefly presented. 
Stanislaw D. Glazek, Arkadiusz P. Trawinski
hep-ph hep-th nucl-th