The top quark in muon + jet events from 1.8 TeV proton-antiproton collisions

Abstract

An optimized search for the top (or truth) quark is performed in tt̄ → μ+ jet events produced by pp̄ collisions with √s= 1.8 TeV at the Fermilab Tevatron and observed with the DØ detector. The data set analyzed is identical to that used by the DØ Collaboration in its reported discovery of the top quark which engaged other decay channels as well. Four events are observed with an expected background' of 1.40 ± 0.71 events. The probability for an upward fluctuation of the background to produce the observed number of events is 0.081 (equivalent to 1.7 standard deviations). An analysis for the top quark mass is carried out based on the amount of jet activity transverse to the pp̄ beam direction. The resultant top quark mass value is measured to be 185(+16)(-26)(stat.)(+6)(-8)(syst.) GeV/c^2 with a corresponding production cross section of 5.3 ± 4.4 pb.