@article{OPUS4-12785, title = {Search for anomaly-mediated supersymmetry breaking with the ATLAS detector based on a disappearing-track signature in pp collisions at √s=7 TeV}, series = {The European Physical Journal C}, volume = {72}, journal = {The European Physical Journal C}, number = {1993}, organization = {ATLAS Collaboration}, doi = {10.1140/epjc/s10052-012-1993-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-127850}, year = {2012}, abstract = {In models of anomaly-mediated supersymmetry breaking (AMSB), the lightest chargino is predicted to have a lifetime long enough to be detected in collider experiments. This letter explores AMSB scenarios in pp collisions at √s=7 TeV by attempting to identify decaying charginos which result in tracks that appear to have few associated hits in the outer region of the tracking system. The search was based on data corresponding to an integrated luminosity of 1.02 fb\(^{-1}\) collected with the ATLAS detector in 2011. The p\(_T\) spectrum of candidate tracks is found to be consistent with the expectation from Standard Model background processes and constraints on the lifetime and the production cross section were obtained. In the minimal AMSB framework with m\(_{3/2}\)<32 TeV, m\(_0\)<1.5 TeV, tanβ=5 and μ>0, a chargino having mass below 92 GeV and a lifetime between 0.5 ns and 2 ns is excluded at 95 \% confidence level.}, language = {en} } @article{AadAbbottAbdallahetal.2012, author = {Aad, G. and Abbott, B. and Abdallah, J. and Abdelalim, A. A. and Abdesselam, A.}, title = {Performance of the ATLAS Trigger System in 2010}, series = {The European Physical Journal C}, volume = {72}, journal = {The European Physical Journal C}, number = {1849}, doi = {10.1140/epjc/s10052-011-1849-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-127321}, year = {2012}, abstract = {Proton-proton collisions at √s=7 TeV and heavy ion collisions at \(\sqrt{sNN}\)=2.76 TeV were produced by the LHC and recorded using the ATLAS experiment's trigger system in 2010. The LHC is designed with a maximum bunch crossing rate of 40 MHz and the ATLAS trigger system is designed to record approximately 200 of these per second. The trigger system selects events by rapidly identifying signatures of muon, electron, photon, tau lepton, jet, and B meson candidates, as well as using global event signatures, such as missing transverse energy. An overview of the ATLAS trigger system, the evolution of the system during 2010 and the performance of the trigger system components and selections based on the 2010 collision data are shown. A brief outline of plans for the trigger system in 2011 is presented.}, language = {en} } @article{OPUS4-12796, title = {Measurement of W\(^{±}\)Z production in proton-proton collisions at √s=7 TeV with the ATLAS detector}, series = {European Physical Journal C}, volume = {72}, journal = {European Physical Journal C}, number = {2173}, organization = {ATLAS Collaboration}, doi = {10.1140/epjc/s10052-012-2173-0}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-127963}, year = {2012}, abstract = {A study of W\(^{±}\)Z production in proton-proton collisions at √s=7 TeV is presented using data corresponding to an integrated luminosity of 4.6 fb\(^{-1}\) collected with the ATLAS detector at the Large Hadron Collider in 2011. In total, 317 candidates, with a background expectation of 68±10 events, are observed in double-leptonic decay final states with electrons, muons and missing transverse momentum. The total cross-section is determined to be σ\(^{tot}_{WZ}\)=19.0\(^{+1.4}_{-1.3}\)(stat.)±0.9(syst.)±0.4(lumi.) pb, consistent with the Standard Model expectation of 17.6\(^{+1.1}_{-1.0}\) pb. Limits on anomalous triple gauge boson couplings are derived using the transverse momentum spectrum of Z bosons in the selected events. The cross-section is also presented as a function of Z boson transverse momentum and diboson invariant mass.}, language = {en} }