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Title: Top quark mass measurements at CDF

Abstract

The mass of the top quark M{sub top} is interesting both as a fundamental parameter of the standard model and as an important input to precision electroweak tests. The Collider Detector at Fermilab (CDF) has a robust program of top quark mass analyses, including the most precise single measurement, M{sub top} = 173.4 {+-} 2.8 GeV/c{sup 2}, using 680 pb{sup -1} of p{bar p} collision data. A combination of current results from CDF gives M{sub top} = 172.0 {+-} 2.7 GeV/c{sup 2}, surpassing the stated goal of 3 GeV/c{sup 2} precision using 2 fb{sup -1} of data. Finally, a combination with current D0 results gives a world average top quark mass of 172.5 {+-} 2.3 GeV/c{sup 2}.

Authors:
;
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
892326
Report Number(s):
FERMILAB-CONF-06-124-E
arXiv eprint number hep-ex/0605092; TRN: US200711%%432
DOE Contract Number:
AC02-76CH03000
Resource Type:
Conference
Resource Relation:
Conference: To appear in the proceedings of 41st Rencontres de Moriond on Electroweak Interactions and Unified Theories, La Thuile, Aosta Valley, Italy, 11-18 Mar 2006
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ACCURACY; FERMILAB COLLIDER DETECTOR; STANDARD MODEL; T QUARKS; Experiment-HEP

Citation Formats

Brubaker, Erik, and /Chicago U., EFI. Top quark mass measurements at CDF. United States: N. p., 2006. Web. doi:10.2172/897065.
Brubaker, Erik, & /Chicago U., EFI. Top quark mass measurements at CDF. United States. doi:10.2172/897065.
Brubaker, Erik, and /Chicago U., EFI. Mon . "Top quark mass measurements at CDF". United States. doi:10.2172/897065. https://www.osti.gov/servlets/purl/892326.
@article{osti_892326,
title = {Top quark mass measurements at CDF},
author = {Brubaker, Erik and /Chicago U., EFI},
abstractNote = {The mass of the top quark M{sub top} is interesting both as a fundamental parameter of the standard model and as an important input to precision electroweak tests. The Collider Detector at Fermilab (CDF) has a robust program of top quark mass analyses, including the most precise single measurement, M{sub top} = 173.4 {+-} 2.8 GeV/c{sup 2}, using 680 pb{sup -1} of p{bar p} collision data. A combination of current results from CDF gives M{sub top} = 172.0 {+-} 2.7 GeV/c{sup 2}, surpassing the stated goal of 3 GeV/c{sup 2} precision using 2 fb{sup -1} of data. Finally, a combination with current D0 results gives a world average top quark mass of 172.5 {+-} 2.3 GeV/c{sup 2}.},
doi = {10.2172/897065},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2006},
month = {Mon May 01 00:00:00 EDT 2006}
}

Conference:
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  • The top quark mass is interesting both as a fundamental parameter of the standard model as well as an important input to precision electroweak tests. The CDF Collaboration has measured the top quark mass with high precision in all decay channels with complementary methods. A combination of the results from CDF gives a top quark mass of 170.5{+-}1.3(stat.){+-}1.8(syst.) GeV/c{sup 2}.
  • No abstract prepared.
  • In this thesis, we present the first exclusive observation of the t -t → hadronic τ + jets decay channel. Using these events, we measure the t -t pair production cross section and the top quark mass in 2.2 fb -1 of data collected with the Collider Detector at Fermilab (CDF). The Tevatron accelerator at Fermilab provides collisions of protons and anti-protons at a center-of-mass energy of √s = 1.96 TeV and is one of only two accelerators in the world with enough energy to produce top quarks. With a branching fraction of nearly 10%, the hadronic τ + jetsmore » decay channel is the third largest t -t decay mode, and it has only been minimally explored. This the first measurement of the t -t pair production cross section in this decay channel at CDF and the first measurement of the top quark mass in this decay channel in the world. The analysis introduces a new method to recover the total momentum of the ν produced in the τ decay and an artificial neural network to reduce the contribution from the largest background source, QCD multijet background. The t -t pair production cross section is extracted by minimizing a negative log likelihood function which compares the number of observed events to the number of expected events for a given t -t cross section. The top quark mass is extracted by minimizing a negative log likelihood function built from signal and ii background probabilities which are based on the matrix elements for t -t production and decay and W + 4 parton production, respectively. Using events selected with exactly 1 hadronically decaying τ, exactly 4 jets with at least 1 identified as having originated from a b quark, and large missing transverse energy, we measure the t -t pair production cross section to be 8.8 ± 3.3 (stat.) ± 2.2 (syst.) pb and the top quark mass to be 172.7±9.3 (stat.) ±3.7 (syst.) GeV. We find both values to be in good agreement with previous measurements in other t -t decay channels, and the cross section to be consistent with next-to-leading order theoretical predictions.« less
  • We report on the most recent measurements of the top quark mass in three decay channels, performed by the CDF Collaboration at the Tevatron collider. We combine these results to obtain a mass value of 176.0 6.5 GeV/ c 2.
  • The top search in the dilepton and lepton plus jets channels with the Collider Detector at Fermilab is presented. The analysis uses a 67 pb{sup {minus}1} sample of p{bar p} collisions at 1.8 TeV. A 4.8{sigma} excess of candidate events establishes the existence of the top quark. The t{bar t} production cross section is measured to be {sigma}{sub t{bar t}} = 7.6{sub {minus}2.0}{sup +2.4} pb with branching Br(t {yields} Wb) = 0.87{sub {minus}0.30}{sup +0.13}(stat) {sub {minus}0.11}{sup +0.13}(syst). The measured mass is M{sub top} = 176{plus_minus}8{plus_minus}10 GeV.