Jets and Measurements of Α S

Following the first realisation that hadronic particles consist of charged fermions known as quarks, held together by bosonic particles known as gluons, it was learnt that the quarks and gluons (“partons”) can never be observed on their own. Any attempt to isolate a quark, for example by knocking it violently out of a hadron in an energetic collision process, does not result in an observable quark (or gluon). Instead, a shower of elementary particles is seen, referred to as a jet, containing the energy of the original quark or gluon. The gluons couple to the quarks by a running coupling constant αs. In this account, we first make some brief notes regarding QCD processes. There follows a survey of recent experimental results regarding jet measurements and what has been learned from them. In particular, we then examine some recent measurements of αs and attempt to make some comparisons.