The Top Quark Affirms the Standard Model

That chapter deals with the so-called Standard Model, a theoretical picture of the basic units of matter that had guided research in particle physics for more than 20 years. Failure to find the top quark would have cast doubt on the Standard Model and forced physicists to rethink their ideas of how the universe is constructed at the most fundamental levels. With the top quark in hand, physicists could begin turning their attention to other questions in their search for the ultimate nature of matter.

It is a search that goes back to the dawn of scientific thinking in ancient Greece. It has been above all a quest for simplicity, motivated by the belief that underlying the complexity and unruliness of the everyday world, there exists a much simpler order. In that realm, far too small for the human eye to see, all matter—whether in the stars above our heads or the dirt beneath our feet—would reveal itself to be made of just a few elementary building blocks.

One of the first thinkers to theorize about matter at the smallest scales was the Greek philosopher Democritus, who lived from about 460 to 370 B.C. Democritus said matter could be reduced to tiny particles that he called atoms, meaning “uncuttable.” He chose that name because he envisioned the particles as being the most basic bits into which anything could be divided. We still use the word atom for the smallest complete unit of an element, such as iron or gold. But in the past 100 years, scientists have learned that atoms, far from being uncuttable, can be split apart into a number of even smaller pieces.