@article{AadAbbottAbdallahetal.2012,
  author    = {Aad, G. and Abbott, B. and Abdallah, J. and Abdel Khalek, S. and Abdelalim, A. A.},
  title     = {Search for the Standard Model Higgs boson in the H→WW(⋆)→ℓνℓνH→WW(⋆)→ℓνℓν decay mode with 4.7 fb\(^{-1}\) of ATLAS data at \(\sqrt{s}\)=7 TeV},
  series = {Physics Letters B},
  volume    = {761},
  journal   = {Physics Letters B},
  number    = {1},
  organization    = {ATLAS Collaboration},
  doi       = {10.1016/j.physletb.2012.08.010},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-127307},
  pages     = {62-81},
  year      = {2012},
  abstract  = {A search for the Standard Model Higgs boson in the H→WW(⋆)→ℓνℓνH→WW(⋆)→ℓνℓν (ℓ=e,μℓ=e,μ) decay mode is presented. The search is performed using proton-proton collision data corresponding to an integrated luminosity of 4.7 fb\(^{-1}\) at a centre-of-mass energy of 7 TeV collected during 2011 with the ATLAS detector at the Large Hadron Collider. No significant excess of events over the expected background is observed. An upper bound is placed on the Higgs boson production cross section as a function of its mass. A Standard Model Higgs boson with mass in the range between 133 GeV and 261 GeV is excluded at 95\% confidence level, while the expected exclusion range is from 127 GeV to 233 GeV.},
  language  = {en}
}
@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}
}
@phdthesis{Meyer2012,
  author    = {Meyer, Jochen},
  title     = {Muon performance aspects and measurement of the inclusive ZZ production cross section through the four lepton final state with the ATLAS experiment at the LHC},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-78793},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2012},
  abstract  = {The "Large Hadron Collider" (LHC) is currently the most powerful particle accelerator. It provides particle collisions at a center of mass energy in the Tera-electronvolt range, which had never been reached in a laboratory before. Thereby a new era in high energy particle physics has began. Now it is possible to test one of the most precise theories in physics, the Standard Model of particle physics, at these high energies. The purpose is particularly served by four large experiments installed at the LHC, namely "A Toroidal LHC ApparatuS" (ATLAS), the "Compact-Muon-Solenoid" (CMS), the "Large Hadron Collider beauty" (LHCb) and "A Large Ion Collider Experiment" (ALICE). Besides exploring the high energy behavior of the well-established portions of the Standard Model, one of the main objectives is to find the Higgs boson included in the model, but not discovered by any preceding effort. It is of tremendous importance since fermions and heavy electroweak gauge bosons acquire mass because of this boson. Although the success of the Standard Model in describing nature is already undisputed, there are some flaws due to observations inexplicable within this theory only. Therefore searches for physics beyond the Standard Model are promoted at the LHC experiments as well. In order to achieve the defined goals, crucial aspects are firstly precise measurements, to verify Standard Model predictions in detail, and secondly an evaluation of as much information as accessible by the detectors, to recognize new phenomena as soon as possible for subsequent optimizations. Both challenges are only possible with a superior understanding of the detectors. An inevitable contribution to attain this knowledge is a realistic simulation, partially requiring new implementation techniques to describe the very complex instrumentation. The research presented here is performed under the patronage of the ATLAS collaboration with a special focus on measurements done with muon spectrometer. Thus a first central issue is the performance of the spectrometer in terms of physics objects that are recognized by the device, the compatibility of data and the existing simulation as well as its improvement and finally the extension of the acceptance region. Once the excellent behavior and comprehension of the muon spectrometer is demonstrated, a second part addresses one physics use case of reconstructed muons. The electroweak force is part of the Standard Model and causes the interaction of heavy electroweak gauge bosons with fermions as well as their self-interaction. In proton-proton collisions such gauge bosons are produced. However, they decay immediately into a pair of fermions. In case of the Z boson, which is one of the gauge bosons, oppositely charged fermions of the same generation, including muons, emerge. The various decay modes are determined precisely at particle accelerators other than the LHC. However, the associated production of two Z bosons is measured less exactly at those facilities because of a very low cross section. The corresponding results acquired with the ATLAS experiment exceed all previous measurements in terms of statistics and accuracy. They are reported in this thesis as obtained from the observation of events with four charged leptons. The enhancement of the signal yield based on the extension of the muon spectrometer acceptance is especially emphasized as well as alternative methods to estimate background events. Furthermore, the impact on the probing of couplings of three Z bosons and intersection with the search for the Standard Model Higgs boson are pointed out.},
  subject      = {ATLAS <Teilchendetektor>},
  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}
}