Thesis submitted to Purdue University, May 1996
by Mark Kruse

Thesis Advisors: Daniela Bortoletto, Arthur Garfinkel

Title
-----
Observation of Top Quark Pair Production in the Dilepton Decay Channel from
Proton-Antiproton Collisions at sqrt(s) = 1.8 TeV

Abstract
--------
This thesis presents the results of a search for the top quark using data
obtained at the Collider Detector at Fermilab (CDF) in p-pbar collisions at a
center-of-mass energy of sqrt(s) = 1.8 TeV.  The data represents an integrated
luminosity of 109 pb^-1.  The search includes the Standard Model t-tbar decays
with final states in the dilepton channel; t-tbar -> l^+ nu b l^- nubar b,
where l = e or mu.  Such events are characterized by 2 high momentum leptons, 2
b quark jets, and missing energy from the undetected neutrinos.  Nine events
were observed to pass the selection based on these characteristics, with an
estimated background of 2.1 +/- 0.4 events.  The probability for an upward
fluctuation of the background to produce the observed signal is 6.3 x 10^-4,
which corresponds to an excess of 3.2 sigma.  The excess is identified as 
t-tbar production,  and gives a measured cross section of 
sigma_ttbar = 8.2 +4.3 -3.3 pb.


Posted to /cdf/pub/thesis/cdf4632_kruse_thesis.ps
    http://www-cdf.fnal.gov/thesis/cdf4632_kruse_thesis.ps

Posted by groer@fnald