TY  - JOUR
T1  - Measurement of τ polarization in W→τν decays with the ATLAS detector in pp collisions at s√=7 TeV
JF  - The European Physical Journal C
N2  - In this paper, a measurement of τ polarization in W→τν decays is presented. It is measured from the energies of the decay products in hadronic τ decays with a single final state charged particle. The data, corresponding to an integrated luminosity of 24 pb\(^{−1}\), were collected by the ATLAS experiment at the Large Hadron Collider in 2010. The measured value of the τ polarization is P\(_τ\)=−1.06±0.04 (stat)\(^{+0.05}_{−0.07}\) (syst), in agreement with the Standard Model prediction, and is consistent with a physically allowed 95 % CL interval [−1,−0.91]. Measurements of τ polarization have not previously been made at hadron colliders.
KW  - total systematic uncertainty
KW  - energy scale uncertainty
KW  - multijet background
KW  - electroweak background
KW  - jet energy
KW  - Monte Carlo methods
KW  - signal template
KW  - track momentum
KW  - calorimeter
KW  - detector track
KW  - transverse momentum
KW  - ATLAS detector
KW  - jet axis
KW  - multijet event
KW  - track multipilicty
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127807
VL  - 72
IS  - 2062
ER  - 
TY  - JOUR
T1  - A search for \(t\overline t\) resonances with the ATLAS detector in 2.05 fb\(^{−1}\) of proton-proton collisions at √s=7 TeV
JF  - European Physical Journal C
N2  - A search for top quark pair resonances in final states containing at least one electron or muon has been performed with the ATLAS experiment at the CERN Large Hadron Collider. The search uses a data sample corresponding to an integrated luminosity of 2.05 fb\(^{−1}\), which was recorded in 2011 at a proton-proton centre-of-mass energy of 7 TeV. No evidence for a resonance is found and limits are set on the production cross-section times branching ratio to \(t\overline t\) for narrow and wide resonances. For narrow Z′ bosons, the observed 95 % Bayesian credibility level limits range from 9.3 pb to 0.95 pb for masses in the range of m Z′=500 GeV to m\(_{Z′}\)=1300 GeV. The corresponding excluded mass region for a leptophobic topcolour Z′ boson (Kaluza-Klein gluon excitation in the Randall-Sundrum model) is m\(_{Z′}\)<880 GeV (m\(_{gKK}\)<1130 GeV).
KW  - dilepton invariant mass
KW  - dilepton channel
KW  - jet channel
KW  - top quark mass
KW  - heavy flavour quark
KW  - reconstructed mass spectrum
KW  - muon channel
KW  - single top production
KW  - electron energy deposition
KW  - multijet background
KW  - non-prompt lepton
KW  - light quark jet
KW  - jet sample
KW  - pair invariant mass
KW  - event selcetion cut
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127959
VL  - 72
IS  - 2083
ER  - 
TY  - JOUR
T1  - Measurement of the charge asymmetry in top quark pair production in pp collisions at √s=7 TeV using the ATLAS detector
JF  - The European Physical Journal C
N2  - A measurement of the top-antitop production charge asymmetry A C is presented using data corresponding to an integrated luminosity of 1.04 fb\(^{−1}\) of pp collisions at √s=7 TeV collected by the ATLAS detector at the LHC. Events are selected with a single lepton (electron or muon), missing transverse momentum and at least four jets of which at least one jet is identified as coming from a b-quark. A kinematic fit is used to reconstruct the t\(\overline t\) event topology. After background subtraction, a Bayesian unfolding procedure is performed to correct for acceptance and detector effects. The measured value of A\(_C\) is AC=−0.019±0.028 (stat.)±0.024 (syst.), consistent with the prediction from the MC@NLO Monte Carlo generator of A\(_C\) =0.006±0.002. Measurements of A\(_C\) in two ranges of invariant mass of the top-antitop pair are also shown.
KW  - jet multiplicity
KW  - B-tagged jet
KW  - systematic uncertainty
KW  - jet energy resolution
KW  - top quark masse
KW  - muon channel
KW  - jet scale energy
KW  - light quark jet
KW  - heavy flavour
KW  - single top production
KW  - single top event
KW  - fake lepton
KW  - top quark pair
KW  - multijet background
KW  - JES
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128904
VL  - 72
IS  - 2039
ER  -