CDF has resumed the top quark mass measurement with upgraded detectors and Tevatron complex. High statistics should allow us to determine the top mass with an uncertainty of a few GeV/c2 by the end of Run II. The current measured value, using an integrated luminosity of (almost equal to) 108 pb−1, is 177.5{sub -9.4}{sup +12.7} (stat.) " 7.1(syst.) GeV/c2 (lepton + jets with one b-jet tagged mode: the current best mode), which is consistent with RunI measurements.
This will be a required acquisition text for academic libraries. More than ten years after its discovery, still relatively little is known about the top quark, the heaviest known elementary particle. This extensive survey summarizes and reviews top-quark physics based on the precision measurements at the Fermilab Tevatron Collider, as well as examining in detail the sensitivity of these experiments to new physics. Finally, the author provides an overview of top quark physics at the Large Hadron Collider.
We report on recent measurements of the top quark mass using t{bar t} candidate events selected in {approx_equal} 320 pb{sup -1} of data from the ''Run II'' operation period of the Tevatron p{bar p} collider. More emphasis is given on the best single measurement to date (M{sub top} = 173.5{sub -3.8}{sup +3.9} GeV/c{sup 2}), provided by CDF using the ''lepton plus jets'' channel, where one W decays to a lepton-neutrino pair and the other into quarks (top quarks decay to Wb almost 100% of the time).
This document presents a measurement of the top quark mass using the CDF run II detector at Fermilab. Colliding beams of protons and anti-protons at Fermilab's Tevatron ([radical]s = 1.96 TeV) produce top/anti-top pairs, which decay to W[sup +]W[sup -] b[bar b]; events are selected where one W decays hadronically, and one W decays to either e or [mu] plus a neutrino. The data sample was collected between March 2002 and September 2003, and corresponds to an integrated luminosity of approximately 162 pb[sup -1]. Thirty-seven candidate t[bar t] events are found with at least one b jet identified by its displaced vertex. In each event, the best fit top quark invariant mass is determined by minimizing a [chi][sup 2] for the overconstrained kinematic system. A likelihood fit of the reconstructed masses in the data sample to distributions from simulated signal and background events gives a top mass of 174.9[sub -7.7][sup +7.1](stat.) [+-] 6.5(syst.) GeV/c[sup 2]. The dominant systematic error is due to uncertainties in the jet energy measurements.
The authors present a measurement of the mass of the top quark from proton-antiproton collisions recorded at the CDF experiment in Run II of the Fermilab Tevatron. They analyze events from the single lepton plus jets final state (t{bar t} --> WbW−{bar b} --> lvbq{bar q}{bar b}). The top quark mass is extracted using a direct calculation of the probability density that each event corresponds to the t{bar t} final state. The probability is a function of both the mass of the top quark and the energy scale of the calorimeter jets, which is constrained in situ by the hadronic W boson mass. Using 167 events observed in 955 pb−1 of integrated luminosity, they achieve the single most precise measurement of the top quark mass, 170.8 ± 2.2(stat.) ± 1.4(syst.) GeV/c2.
We report a measurement of the top quark mass with the upgraded Collider Detector at Fermilab (CDF-II). The top quarks are produced in pairs (tt−) in proton-antiproton collisions with a center-of-mass energy of 1.96 TeV. Each top quark decays to a W boson and a bottom quark. We select candidate events in which one W boson decays hadronically and the other decays to an electron or a muon and its associated neutrino. The data sample, which corresponds to an integrated luminosity of 318 pb-1, contains 138 tt− candidates. A top quark mass is reconstructed for each event by placing energy and momentum constraints on the top quark pair decay products. We also employ the reconstructed mass of the hadronic W boson decays W & rarr; jj to constrain in situ the largest systematic uncertainty of the top quark mass measurement, the jet energy scale. Monte Carlo templates of the reconstructed top quark and W boson mass are produced as a function of the top quark mass and the jet energy scale. The distribution of reconstructed top quark and W boson mass in the data are compared to the Monte Carlo templates using a likelihood fit to obtain Mtop = 173.5+3.9-3.8 GeV/c2. This constitutes the most precise measurement of the top quark mass to date. This measurement can be used to constrain the mass of the Higgs boson, a central particle in the Standard Model of particle physics that has yet to be observed. We also demonstrate that this new technique reduces naturally the jet, energy scale uncertainty as more data is accumulated and thus provides the capability to measure Mtop with an uncertainty of 2 GeV/c2 or better by the end of the CDF-II experiment.
