Top quark physics: from Tevatron to LHC Page: 1 of 9
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TOP QUARK PHYSICS: FROM TEVATRON TO LHC
H. Physikalisches Institut, Universitit Gdttingen, Friedrich-Hund-Platz 1
D-37077 Gdttingen, Germany
We present an overview of the recent measurements of the top quark production cross sections,
top quark properties and searches in the top sector at the Fermilab Tevatron proton-antiproton
collider at a center-of-mass energy of fi = 1.96 TeV using up to 5.6 fb-i of collision data.
We also discuss the prospects of top quark physics with the early LHC proton-proton data
being collected at a center-of-mass energy of f = 7 TeV.
The large sample of top-antitop quark pairs collected by the DO amd CDF experiments at
the Fermilab Tevatron collider allows to perform precision measurements of the fundamental
top quark characteristics, such as its production cross section and mass, and to study a broad
variety of top quark production and decay properties to address the question whether the top
quark is indeed the particle predicted by the standard model (SM). In this paper, we review
recent new measurements of top quark cross sections, mass, width, forward-backward charge
asymmetry and spin correlations in tt production and some direct searches for new physics
in the top quark sector. We also present the prospects of the first top quark production and
properties measurements at the new energy frontier achieved in the ongoing run of LHC.
2 Top quark production
Within the SM, top quarks are produced either in pairs via strong interactions or as single top
events via electroweak interactions. Each top quark decays almost 100% of the time to a W
boson and a b-quark. W bosons can decay leptonically into an electron, muon or tau and a
corresponding neutrino, or hadronically into quark-antiquark pairs. Thus, the final states of tt
events are subdivided into the dilepton (ff) channels with both W bosons decaying leptonically,
the lepton+jets (f-+jets) channels, where one of the W bosons decays leptonically and the other
one hadronically, and the all hadronic channel, where both W bosons decay hadronically.
2.1 Top quark pairs
In the Tevatron pp collisions at A/s = 1.96 TeV, top quark pair production occurs via qq annihi-
lation (85%) or gluon fusion (15%). In the pp collisions at the LHC top quark pair production
is dominated by gluon fusion (~ 90%). The latest theoretical calculations of the t4 production
cross section ' have an uncertainty of - 5 - 8%. Any deviation of its measured value from the
SM prediction could signal the presence of new physics in top-pair production or decays.
Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH1 1359 with the United States Department of Energy.
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Shabalina, E.K. & /Gottingen U., II. Phys. Inst. Top quark physics: from Tevatron to LHC, article, October 1, 2010; Batavia, Illinois. (digital.library.unt.edu/ark:/67531/metadc1012260/m1/1/: accessed October 19, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.