Editing UA2 experiment (section)

===Search for the top quark===
Throughout the runs with the upgraded detector, the UA2 collaboration was in competition with experiments at [[Fermilab]] in the US in the search for the [[top quark]]. Physicists had anticipated its existence since 1977, when its partner — the [[bottom quark]] — was discovered. It was felt that the discovery of the top quark was imminent.

During the 1987-1990 run UA2 collected 2065 <math> W \rightarrow e \nu </math> decays, and 251 Z decays to electron pairs, from which the ratio of the mass of the W boson and the mass of the Z boson could be measured with a precision of 0.5%.<ref name=Rubbia/> By 1991 a precise measurement for the mass of the Z boson from LEP had become available. Using the ratio of the W mass to Z mass, a first precise measurement of the W mass could be made. These mass values could be used to predict the top quark from its virtual effect on the W mass. The result of this study gave a top quark mass value in the range of 110 GeV to 220 GeV,<ref name=Rubbia/> beyond the reach for direct detection by UA2 at the Sp{{overline|p}}S. The top quark was ultimately discovered in 1995 by physicists at Fermilab with a mass near 175 GeV.<ref name=CDF-1995>{{cite journal |author=F. Abe|display-authors=etal |year=1995 |title=Observation of Top Quark Production in {{SubatomicParticle|Antiproton}}{{SubatomicParticle|Proton}} Collisions with the Collider Detector at Fermilab |journal=[[Physical Review Letters]] |volume=74 |issue=14 |pages=2626–2631 |doi=10.1103/PhysRevLett.74.2626 |pmid=10057978 |bibcode=1995PhRvL..74.2626A|arxiv=hep-ex/9503002 |hdl=2241/103691 |s2cid=119451328 |url=https://zenodo.org/record/1233901 }}</ref><ref name=D0-1995>{{cite journal |author=S. Abachi|display-authors=etal  |year=1995 |title=Search for High Mass Top Quark Production in {{SubatomicParticle|Proton}}{{SubatomicParticle|Antiproton}} Collisions at {{radical|''s''}}&nbsp;=&nbsp;1.8&nbsp;TeV |journal=[[Physical Review Letters]] |volume=74 |issue=13 |pages=2422–2426 |doi=10.1103/PhysRevLett.74.2422 |pmid=10057924  |bibcode=1995PhRvL..74.2422A|arxiv=hep-ex/9411001 |s2cid=119392677 }}</ref>