The discovery of the top quark

Abstract

Evidence for pair production of a new particle consistent with the Standard Model top quark has been reported recently by groups studying proton anti-proton collisions at 1.8 TeV center of mass energy at the Fermi National Accelerator Laboratory. In this paper we review the history of the search for the top quark in electron positron and proton anti-proton collisions. We report on a number of precise electro-weak measurements and the value of the top quark mass which can be extracted from these measurements within the context of the Standard Model. We review the theoretical predictions for top quark production and the dominant backgrounds. We describe the collider and the detectors that were used to measure the pair production process and follow on to describe the data from which the existence of the top quark is evinced. Finally, we present possible measurements that could be made in the future with more data, measurements of quantities that would confirm the nature of this particle, the details of its production in hadron collisions, and its decay properties.Comment: To be published in Reviews of Modern Physics. Also available at http://charm.physics.ucsb.edu/people/claudio/rmp.htm

Large Pt processes in ppbar collisions at 2 TeV: measurement of ttbar production cross section in ppbar collisions at s**(1/2) = 1.96 TeV in the dielectron final states at the D0 experiment

“…We present a brief historical survey of the top quark searches. A more complete review is given in reference [27].…”

“…well above the energy threshold for the production of a tt pair [27]. GeV from searches in electron-muon + jets final states [53], M top > 77 GeV from searches in electron plus jets final states [54], and M top > 85 GeV from searches in dilepton final states [55].…”

Measurements of the Top Anti-Top Production Cross Section and Top Quark Mass in the Hadronically Decaying Tau + Jets Decay Channel at CDF

“…It was discovered at Fermilab in 1995 [13] [14] [15]. It is by far the heaviest of all the elementary particles with a mass of 173.2 ± 0.9 GeV as measured at the Tevatron as of July 2011 with 5.8 fb −1 of data [16].…”

Measurement of single top quark production in the tau+jets channnel using boosted decision trees at D0

“…It is not part of the Standard Model of particle physics and will not be discussed here. [8]. This discovery was based on top quark pair production via the strong interaction.…”