The experiment road to the heavier quarks and other heavy objects

Abstract

Abstract. After a brief history of heavy quarks, I will discuss charm, bottom, and top quarks in turn. For each one, I discuss its first observation, and then what we have learned about production, hadronization, and decays -and what these have taught us about the underlying physics. I will also point out remaining open issues. For this series of lectures, the charm quark will be emphasized. It is the first of the heavy quarks, and its study is where many of the techniques and issues first appeared. Only very brief mention is made of CP violation in the bottom-quark system since that topic is the subject of a separate series of lectures by Gabriel Lopez. As the three quarks are reviewed, a pattern of techniques and lessons emerges. These are identified, and then briefly considered in the context of anticipated physics signals of the future; e.g., for Higgs and SUSY particles. A BRIEF HISTORY OF HEAVY QUARKS Today's Elementary ParticlesToday's picture of the most elementary particles is composed of six quark types, six lepton types, and four force carriers. The quarks and leptons come in three generations, each generation with a pair of quarks (one with charge + 2/3, and one with charge -1/3) and a pair of leptons (one charged, and one neutral). See Table 1. The quarks and leptons have spin 1/2, and couple variously to the spin 1 force carriers: gluons, photons, and charged and neutral weak bosons (W + , W − , and Z). Unlike the leptons, the quarks appear to come in three varieties, called colors. Perhaps the number of colors is related to the quarks' third-integer charges. Also, quarks never appear in isolation, being permanently confined, for example, in meson and baryon combinations (quark-antiquark and three-quark combinations, respectively).These quark, lepton, and force-carrying particles are the foundation of the socalled Standard Model of particle physics. It is widely and completely accepted by the community. However, it was not always that way. The acceptance of the quark