Evidence for pair production of a new particle consistent with the standard-model top quark has been reported recently by groups studying proton-antiproton collisions at 1.8 TeV center-of-mass energy at the Fermi National Accelerator Laboratory. This paper both reviews the history of the search for the top quark in electron-positron and proton-antiproton collisions and reports on a number of precise electroweak measurements and the value of the top-quark mass that can be extracted from them. Within the context of the standard model, the authors review the theoretical predictions for top-quark production and the dominant backgrounds. They describe the collider and the detectors that were used to measure the pair-production process and the data from which the existence of the top quark is evinced. Finally, they suggest possible measurements that could be made in the future with more data, measurements that would confirm the nature of this particle, the details of its production in hadron collisions, and its decay properties.

DOI:https://doi.org/10.1103/RevModPhys.69.137