TY  - JOUR
T1  - Search for light scalar top-quark pair production in final states with two leptons with the ATLAS detector in √s=7 TeV proton–proton collisions
JF  - The European Physical Journal C
N2  - A search is presented for the pair production of light scalar top quarks in √s=7 TeV proton–proton collisions recorded with the ATLAS detector at the Large Hadron Collider. This analysis uses the full data sample collected during 2011 running that corresponds to a total integrated luminosity of 4.7 fb\(^{−1}\). Light scalar top quarks are searched for in events with two opposite-sign leptons (e, μ), large missing transverse momentum and at least one jet in the final state. No excess over Standard Model expectations is found, and the results are interpreted under the assumption that the light scalar top decays to a b-quark in addition to an on-shell chargino whose decay occurs through a virtual W boson. If the chargino mass is 106 GeV, light scalar top-quark masses up to 130 GeV are excluded for neutralino masses below 70 GeV.
KW  - signal cross section
KW  - jet energy scale
KW  - jet energy scale uncertainty
KW  - dead region
KW  - jet energy resolution
KW  - top quark pair
KW  - charingo mass
KW  - top quark decay
KW  - SM background
KW  - simulaed event sample
KW  - MC simulation
KW  - visible cross section
KW  - anti-k jet
KW  - top event dilepton invariant mass
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-129561
VL  - 72
IS  - 2237
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  - 
TY  - JOUR
T1  - Search for second generation scalar leptoquarks in pp collisions at √s=7 TeV with the ATLAS detector
JF  - The European Physical Journal C
N2  - The results of a search for the production of second generation scalar leptoquarks are presented for final states consisting of either two muons and at least two jets or a muon plus missing transverse momentum and at least two jets. A total of 1.03 fb\(^{−1}\) integrated luminosity of proton-proton collision data produced by the Large Hadron Collider at s√=7 TeV and recorded by the ATLAS detector is used for the search. The event yields in the signal regions are found to be consistent with the Standard Model background expectations. The production of second generation leptoquarks is excluded for a leptoquark mass m\(_{LQ}\)<594 (685) GeV at 95 % confidence level, for a branching ratio of 0.5 (1.0) for leptoquark decay to a muon and a quark.
KW  - jet energy scale
KW  - top quark mass
KW  - multi-jet background
KW  - simulated event sample
KW  - SM background
KW  - acceptance time efficiency
KW  - top quark contribution
KW  - top quark pair
KW  - primary vertex
KW  - single top quark production
KW  - signal cross section
KW  - systematic uncertainty
KW  - single top quark
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128957
VL  - 72
IS  - 2151
ER  -