Could someone please give me some references or the name of the theory for gauge theories using 'nice' gauge transformations, eg. transformations whose first derivatives in space are bounded? Why I ask that: my question is if we shouldn't take essential properties of quantum mechanics more serious. If we need high energies to recognize elementary particles as dirac particles, why do we assume them to be dirac particles at low energies? My idea is that analytical properties of the gauge transformations represent the dirac nature of particles (local charge conservation in contrast to global charge conservation). Could it be that this prejudice (of local gauge invariance) limits pQCD to the regime of large Q^2? What happens if we weaken local gauge invariance somewhat?