DP Seminar

[Luca Ferialdi]

Department of Physics - University of Trieste

Wednesday 13 April 2011 - 3.00 pm
Room 204 (2nd floor LB)

Mr. Michele Pinamonti
(University of Trieste)

Title: Top physics with the ATLAS detector at the LHC

Abstract:
The top quark, the heaviest known elementary particle of the Standard
Model with a mass of 173 GeV, is copiously produced at the LHC, where two
high intensity proton beams collide with a center of mass energy of 7 TeV.
The properties of its production and decay can be studied by identifying
and reconstructing its decay products. Thanks to the excellent
performances of the ATLAS detector, which is able to identify and measure
electrons, muons, hadronic jets, heavy flavour jets and neutrinos with a
wide range of energies and an almost complete angular acceptance, the top
physics at ATLAS is now reaching high levels of precision, starting to
compete with the Tevatron experiments CDF and D0.

The main results so far have been the measurements the production
cross-section in the different production and decay channels (with the
best precision reached in the top-antitop semi-leptonic channel). A
measurement which can be of particular interest and which will be feasible
within the end of the 2011 is the top-antitop angular production asymmetry
in top-antitop pair production. The measurement of this quantity at both
CDF and D0 shows a big discrepancy with the Standard Model prediction
which is not yet understood. A confirmation of this discrepancy at the LHC
can be the first clear signal of new physics beyond the Standard Model.