What Is Renormalization Theory and Why Is It a Criterion in Developing and Describing the Fundamental Interactions in Nature?

Abstract

What is renormalization theory? Remember that when you write down a Lagrangian density, the parameters (couplings and masses) in it are so-called unrenormalized parameters introduced, formally, at infinite energies, all the way corresponding to measurements made at absolute zero distances and are physically unattainable and one should not be surprised if they are often ill defined theoretically. It is certainly not justifiable to think that our theories may be extended all the way to infinite energies.