Measurement of the top quark/anti-top quark production cross section in the lepton plus jets channel in proton-antiproton collisions at 1.8 TeV.

Abstract

The direct observation of the top quark was first achieved at the Tevatron proton-antiproton collider at Fermilab. This discovery completed the third generation fermion sector where the top quark is expected to accompany the bottom quark in the weak isospin doublet. This dissertation will discuss the experimental verification of the production cross section as predicted by the Standard Model. A measurement of the tt production cross section using 110 pb$\sp{-1}$ of pp Collisions at $\sqrt{s}=1.8$ TeV collected with the Collider Detector at Fermilab between August of 1992 and February of 1996 is presented. The measurement focuses on the tt production in the lepton plus jets final state in which one of the W bosons from tt decay subsequently decays leptonically to an e or $\mu,$ and the other hadronically, i.e., $t\bar t\to(q\bar q\sp\prime b)(e\nu\bar b),$ or $t\bar t\to(q\bar q\sp\prime b)(\mu\nu\bar b).$ The b-tagging technique which utilizes the precision silicon detector tracking is used to enhance the signal, relative to the backgrounds for tt events, by identification the bottom quark from its measurable lifetime. With the top mass found to be 175 $GeV/c\sp2$ in CDF, the tt production cross section is measured to be $\sigma\sb{t\bar t}=6.0\sbsp{-1.8}{+2.2}pb.$