Chapter 1: The Standard Model and Beyond

A famous quote attributed to Albert Einstein says “The most incomprehensible thing about the world is that it is comprehensible.” If one looks at the depth of our current understanding of subnuclear physics, one has to agree with the great Einstein. Humans have succeeded in explaining natural phenomena down to mind-bogglingly small distance scales, and such is an extraordinary accomplishment; yet, even more surprising is the fact that a theoretical explanation was there to be unearthed in the first place. The standard model is that theory. It results from unifying together into a single elegant construction the mathematical descriptions of phenomena involving three apparently unrelated natural forces: the electromagnetic interaction, which holds atoms together and describes the forces acting on electrically charged bodies; the weak interaction, which helps make stars burn and causes the radioactive decay of heavy elements; and the strong interaction, to which we owe the stability of atomic nuclei. These forces act on matter particles, so it is useful to introduce the latter before we explain how forces work.