Introducing scale symmetry

When symmetries are present the solution of almost any physical problem is simplified, because we can get at the properties of a system without completely solving all the equations that describe the system. In high‐energy physics, symmetry principles have been studied with an eye to circumventing two obstacles to the understanding of elementary particles: lack of precise knowledge about interparticle forces (with the exception of electromagnetism) and the mathematical intractability of any realistic models that propose to explain observed particle phenomena.