Measurement of the Top-quark Pair Production Cross-section Using Final States with a Lepton and a Hadronically Decaying Tau-lepton

October 2, 2012 12:00PM to 1:00PM
Presenter
Yuta Takahashi, Nagoya University
Location
Building 362, Room F108
Type
Seminar
Series
HEP Lunch Seminar
Food will be ordered, but use the signup sheets, as usual, to place your order by 10:30 a.m. on October 2.

Abstract:
Measurement of the $t\bar{t}$ production cross section using final states characterized by an electron or muon and one hadronically decaying $\tau$-lepton is reported using 2.05 fb$^{-1}$ $pp$ collision data accumulated by the ATLAS detector at the LHC. This measurement is not only the verification of the standard model but also looking ahead the search for new physics such as charged Higgs boson production, which in some scenarios predominantly decays into a $tau$ and a neutrino. The analysis exploits a multi-variate technique that provides a large separation power between signal and background, as well as data-driven background estimates in order to minimize systematic uncertainty. With a total uncertainty of 13%, the observed cross section was found to be consistent with the Standard Model expectation, demonstrating the validity of the theory at the LHC energy scale.