Top quark mass: latest CDF results, Tevatron combinations, and electroweak implications
We present results on the precision measurement of the top quark mass, the difference between the top and antitop quark mass, and a combination of the best CDF top mass measurements. We present also a combination by the TevEWWG (Tevatron electroweak working group) of the best top mass results from CDF and D0 in Run 1 and Run 2 of the Tevatron. This result is the current world average, and offers an uncertainty of about 1GeV. The new mass value has been included in traditional LEP EWWG fits to precision electroweak data, and implications for the Standard Model Higgs have been derived.
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Top quark production:
We present the most precise cross section measurements of pair and singly produced top quarks by the CDF experiment. We measured the ttbar cross section in all decay modes, finding good agreement with among measurements and channels, and combine them to achieve precision comparable to NLO QCD calculation. Single top candidate events are selected for classification by several parallel analysis techniques: likelihood discriminant, matrix-element discriminant, boosted decision trees, and neural networks. The results of these analyses are combined in order to improve the expected sensitivity. We also present the most current value of the CKM matrix element Vtb.
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Measurement of top pair spin correlations using CDF Run II data
Top quark spin is one of the most interesting, yet not well-measured,
quantities in top physics. Standard model top pair production
through qq annihilation or gluon fusion produces a characteristic
spin correlation which can be modified by exotic production
mechanisms such as Z' bosons or KK gluons. According to the standard
model, top quarks decay weakly before any hadronization processes
take effect. This enables top quark spin information to be
transmitted to the top quark decay products. We report on
measurements of the t-tbar spin correlation using lepton+jet and
dilepton events in over 5 fb-1 of CDF data. The results are
combined and the result is the most precise determination of t-tbar spin
correlation to date.
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Measurement of the Forward Backward asymmetry in top-antitop quark pairs at CDF
A method of reconstructing t-tbar events in the lepton plus jets decay mode
is applied to a measurement of the forward backward asymmetry in t-
tbar pair production at CDF. The measurement is a test of discrete
symmetries in t-tbar production and strong interactions at large
Q^2. In the present data set it is potentially sensitive to the
presence of parity-violating production channels such as a massive
Z'- like boson or new physics within strong interactions. We present
a measurement of the top quark forward-backward asymmetry in over 5
fb-1 of collected CDF Run II data.
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Search for Heavy 4th generation Quarks in 1.96-TeV ppbar Collisions
Fifteen years since the discovery of top at the Tevatron, with the large Run 2 dataset in hand and plenty of analysis experience, we have now reached the point where we can perform in-depth examinations of the top quark event sample for evidence of physics beyond the Standard Model. We present a search for a massive quark (t') decaying to Wq or Wb and thus mimicking the top quark decay signature, or massive quark (b') decaying to tW. We use peculiar kinematic distributions in the event to discriminate possible new quarks or other particles from Standard Model processes, and set limits on a 4th generation t' and b' quarks using over 5fb-1 of collected CDF Run II data.
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Search for singly produced heavy quarks at the Tevatron
We present a search for new vector-like heavy quarks in p-pbar collisions at sqrt(s)=1.96 TeV. We do a model-independent search for singly produced heavy quarks decaying to a W boson and a light flavor quark in events with an electron or muon, missing energy, and two hadronic jets. First results in a data sample corresponding to 4.6 /fb of integrated luminosity collected by the CDF detector are presented.
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Searches for resonant top-antitop production at CDF
We describe searches for resonant top-antitop production in over 5fb-1 of 1.96 TeV proton-antiproton collisions at the Tevatron, using data collected by the CDF collaboration. Resonant top pair production could arise from the decays of massive Z-like bosons in extended gauge theories, KK states of the gluon or Z, axigluons, topcolor, and other BSM theories. We use different techniques to study the top- antitop invariant mass spectrum and the mass of boosted top quarks to set model independent limits on new resonant top- antitop production mechanisms.
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