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 - A search for \(t\overline t\) resonances in lepton+jets events with highly boosted top quarks collected in pp collisions at √s=7 TeV with the ATLAS detector JF - Journal of High Energy Physics N2 - A search for resonant production of high-mass top-quark pairs is performed on 2.05 fb\(^{−1}\) of proton-proton collisions at √s=7 TeV collected in 2011 with the ATLAS experiment at the Large Hadron Collider. This analysis of the lepton+jets final state is specifically designed for the particular topology that arises from the decay of highly boosted top quarks. The observed \(t\overline t\) invariant mass spectrum is found to be compatible with the Standard Model prediction and 95% credibility level upper limits are derived on the \(t\overline t\) production rate through new massive states. An upper limit of 0.7 pb is set on the production cross section times branching fraction of a narrow 1 TeV resonance. A Kaluza-Klein gluon with a mass smaller than 1.5 TeV is excluded. KW - hadron-hadron scattering Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-129555 VL - 09 IS - 41 ER - TY - JOUR T1 - Search for doubly charged Higgs bosons in like-sign dilepton final states at √s=7 TeV with the ATLAS detector JF - The European Physical Journal C N2 - A search for doubly charged Higgs bosons decaying to pairs of electrons and/or muons is presented. The search is performed using a data sample corresponding to an integrated luminosity of 4.7 fb\(^{−1}\) of pp collisions at √s = 7 TeV collected by the ATLAS detector at the LHC. Pairs of prompt, isolated, high-p\(_T\) leptons with the same electric charge (\(e^±e^±, e^±μ^±, μ^±μ^±\)) are selected, and their invariant mass distribution is searched for a narrow resonance. No significant excess over Standard Model background expectations is observed, and limits are placed on the cross section times branching ratio for pair production of doubly charged Higgs bosons. The masses of doubly charged Higgs bosons are constrained depending on the branching ratio into these leptonic final states. Assuming pair production, coupling to left-handed fermions, and a branching ratio of 100 % for each final state, masses below 409 GeV, 375 GeV, and 398 GeV are excluded for \(e^±e^±, e^±μ^±\), and \(μ^±μ^±\), respectively. KW - background expectation KW - cross section time KW - acceptance time efficiency KW - partial decay width KW - WZ production KW - extrapolation factor KW - dilepton mass KW - charge misidentification KW - systematic uncertainty KW - non-prompt lepton KW - neutral Higgs boson KW - producation cross section KW - invariant mass distribution KW - MC simulation KW - leptonic final state Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-129540 VL - 72 IS - 2244 ER - TY - JOUR T1 - Search for R-parity-violating supersymmetry in events with four or more leptons in √s=7 TeV pp collisions with the ATLAS detector JF - Journal of High Energy Physics N2 - A search for new phenomena in final states with four or more leptons (electrons or muons) is presented. The analysis is based on 4.7 fb\(^{−1}\) of √s=7 TeV proton-proton collisions delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in two signal regions: one that requires moderate values of missing transverse momentum and another that requires large effective mass. The results are interpreted in a simplified model of R-parity-violating supersymmetry in which a 95% CL exclusion region is set for charged wino masses up to 540 GeV. In an R-parity-violating MSUGRA/CMSSM model, values of m 1/2 up to 820 GeV are excluded for 10 < tan β < 40. KW - hadron-hadron scattering Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-129179 VL - 12 IS - 124 ER - TY - JOUR T1 - Search for charged Higgs bosons decaying via H\(^±\) → τν in \(t\overline t\) events using pp collision data at √s=7 TeV with the ATLAS detector JF - Journal of High Energy Physics N2 - The results of a search for charged Higgs bosons are presented. The analysis is based on 4.6fb\(^{−1}\) of proton-proton collision data at √s=7TeV collected by the ATLAS experiment at the Large Hadron Collider, using top quark pair events with a τ lepton in the final state. The data are consistent with the expected background from Standard Model processes. Assuming that the branching ratio of the charged Higgs boson to a τ lepton and a neutrino is 100 %, this leads to upper limits on the branching ratio of top quark decays to a b quark and a charged Higgs boson between 5% and 1% for charged Higgs boson masses ranging from 90 GeV to 160 GeV, respectively. In the context of the m\(^{max}_h\) scenario of the MSSM, tan β above 12-26, as well as between 1 and 2-6, can be excluded for charged Higgs boson masses between 90 GeV and 150 GeV. KW - hadron-hadron scattering Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-129163 VL - 06 IS - 39 ER - TY - JOUR T1 - Jet mass and substructure of inclusive jets in √s=7 TeV pp collisions with the ATLAS experiment JF - Journal of High Energy Physics N2 - Recent studies have highlighted the potential of jet substructure techniques to identify the hadronic decays of boosted heavy particles. These studies all rely upon the assumption that the internal substructure of jets generated by QCD radiation is well understood. In this article, this assumption is tested on an inclusive sample of jets recorded with the ATLAS detector in 2010, which corresponds to 35 pb\(^{−1}\) of pp collisions delivered by the LHC at √s=7TeV. In a subsample of events with single pp collisions, measurements corrected for detector efficiency and resolution are presented with full systematic uncertainties. Jet invariant mass, k\(_t\) splitting scales and N-subjettiness variables are presented for anti-k\(_t\) R = 1.0 jets and Cambridge-Aachen R = 1.2 jets. Jet invariant-mass spectra for Cambridge-Aachen R = 1.2 jets after a splitting and filtering procedure are also presented. Leading-order parton-shower Monte Carlo predictions for these variables are found to be broadly in agreement with data. The dependence of mean jet mass on additional pp interactions is also explored. KW - hadron-hadron scattering Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128970 VL - 05 IS - 128 ER - TY - JOUR T1 - Search for same-sign top-quark production and fourth-generation down-type quarks in pp collisions at √s=7 TeV with the ATLAS detector JF - Journal of High Energy Physics N2 - A search is presented for same-sign top-quark production and down-type heavy quarks of charge −1/3 in events with two isolated leptons (e or μ) that have the same electric charge, at least two jets and large missing transverse momentum. The data are selected from pp collisions at √s=7TeV recorded by the ATLAS detector and correspond to an integrated luminosity of 1.04 fb\(^{−1}\). The observed data are consistent with expectations from Standard Model processes. Upper limits are set at 95 % confidence level on the cross section of new sources of same-sign top-quark pair production of 1.4-2.0 pb depending on the assumed mediator mass. Upper limits are also set on the pair-production cross-section for new heavy down-type quarks; a lower limit of 450 GeV is set at 95 % confidence level on the mass of heavy down-type quarks under the assumption that they decay 100 % of the time to W t. KW - hadron-hadron scattering Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128960 VL - 04 IS - 69 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 - TY - JOUR T1 - Measurement of \(t\overline t\) production with a veto on additional central jet activity in pp collisions at √s=7 TeV using the ATLAS detector JF - European Physical Journal C N2 - A measurement of the jet activity in \(t\overline t\) events produced in proton–proton collisions at a centre-of-mass energy of 7 TeV is presented, using 2.05 fb\(^{−1}\) of integrated luminosity collected by the ATLAS detector at the Large Hadron Collider. The \(t\overline t\) events are selected in the dilepton decay channel with two identified b-jets from the top quark decays. Events are vetoed if they contain an additional jet with transverse momentum above a threshold in a central rapidity interval. The fraction of events surviving the jet veto is presented as a function of this threshold for four different central rapidity interval definitions. An alternate measurement is also performed, in which events are vetoed if the scalar transverse momentum sum of the additional jets in each rapidity interval is above a threshold. In both measurements, the data are corrected for detector effects and compared to the theoretical models implemented in MC@NLO, Powheg, Alpgen and Sherpa. The experimental uncertainties are often smaller than the spread of theoretical predictions, allowing deviations between data and theory to be observed in some regions of phase space. KW - jet reconstruction efficiency KW - jet energy scale KW - jet energy scale uncertainty KW - fiducial cross section KW - individual systematic uncertainty KW - jet energy resolution KW - systematic uncertainty KW - muon reconstruction efficiency KW - rapidity interval KW - pythia parton shower KW - jet transverse momentum KW - underlying event tune KW - particle level jet KW - additional jet KW - MC event generator Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128931 VL - 72 IS - 2043 ER - TY - JOUR T1 - Measurement of the cross section for top-quark pair production in pp collisions at √s=7TeV with the ATLAS detector using final states with two high-p\(_T\) leptons JF - Journal of High Energy Physics N2 - A measurement is reported of the production cross section of top-quark pairs (\(t\overline t\)) in proton-proton collisions at a center-of-mass energy of 7 TeV recorded with the ATLAS detector at the LHC. Candidate events have a signature consistent with containing two isolated leptons, large missing transverse momentum, and at least two jets. Using a data sample corresponding to an integrated luminosity of 0.70 fb\(^{−1}\), a \(t\overline t\) production cross section σ\(_{t\overline t}\)=176±5(stat.)\(^{+14}_{−11}\)(syst.)±8(lum.) pb is measured for an assumed top-quark mass of m\(_t\)  = 172.5 GeV. This measurement is in good agreement with Standard Model predictions. KW - hadron-hadron scattering Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128924 VL - 5 IS - 59 ER - TY - JOUR T1 - Measurement of the top quark mass with the template method in the \(t\overline t\)→lepton+jets channel using ATLAS data JF - The European Physical Journal C N2 - The top quark mass has been measured using the template method in the \(t\overline t\)→lepton+jets channel based on data recorded in 2011 with the ATLAS detector at the LHC. The data were taken at a proton-proton centre-of-mass energy of √s=7 TeV and correspond to an integrated luminosity of 1.04 fb\(^{−1}\). The analyses in the e+jets and μ+jets decay channels yield consistent results. The top quark mass is measured to be m\(_{top}\)=174.5±0.6\(_{stat}\)±2.3\(_{syst}\) GeV. KW - JES uncertainty KW - jet energy scale KW - top quark mass KW - jet channel KW - single top quark KW - jet energy scale uncertainty KW - systematic uncertainty KW - calorimeter response KW - simulated signal event KW - top quark decay KW - jet reconstruction efficiency KW - jet energy measurement KW - light quark jet KW - single top quark production KW - inclusive jet sample Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128912 VL - 72 IS - 2046 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 - A search for flavour changing neutral currents in top-quark decays in pp collision data collected with the ATLAS detector at √s=7 TeV JF - Journal of High Energy Physics N2 - A search for flavour changing neutral current (FCNC) processes in top-quark decays by the ATLAS Collaboration is presented. Data collected from pp collisions at the LHC at a centre-of-mass energy of √s=7TeV during 2011, corresponding to an integrated luminosity of 2.1 fb\(^{−1}\), were used. A search was performed for top-quark pair-production events, with one top quark decaying through the t → Zq FCNC (q = u, c) channel, and the other through the Standard Model dominant mode t → W b. Only the decays of the Z boson to charged leptons and leptonic W -boson decays were considered as signal. Consequently, the final-state topology is characterised by the presence of three isolated charged leptons, at least two jets and missing transverse momentum from the undetected neutrino. No evidence for an FCNC signal was found. An upper limit on the t → Zq branching ratio of BR(t → Zq) < 0.73% is set at the 95% confidence level. KW - neutral currents KW - rare decays KW - top physics KW - hadron hadron scattering KW - flavour changing Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-129152 VL - 9 IS - 139 ER - TY - JOUR T1 - Search for supersymmetry in events with large missing transverse momentum, jets, and at least one tau lepton in 7 TeV proton-proton collision data with the JF - The European Physical Journal C N2 - A search for supersymmetry (SUSY) in events with large missing transverse momentum, jets, and at least one hadronically decaying τ lepton, with zero or one additional light lepton (e/μ), has been performed using 4.7 fb\(^{−1}\) of proton-proton collision data at \(\sqrt s\)=7TeV recorded with the ATLAS detector at the Large Hadron Collider. No excess above the Standard Model background expectation is observed and a 95 % confidence level visible cross-section upper limit for new phenomena is set. In the framework of gauge-mediated SUSY-breaking models, lower limits on the mass scale Λ are set at 54 TeV in the regions where the \(\tilde τ_1\) is the next-to-lightest SUSY particle (tanβ>20). These limits provide the most stringent tests to date of GMSB models in a large part of the parameter space considered. KW - multi-jet background KW - jet energy scale KW - systematic uncertainty KW - jet background KW - anti-k jet KW - jet energy resolution KW - MC expectation KW - GMSB model KW - Cl Lowe limit KW - transverse momentum KW - single top event KW - SM background KW - MC simulation KW - transverse momentum vector KW - SUSY breaking scale Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128891 VL - 72 IS - 2215 ER - TY - JOUR T1 - ATLAS search for a heavy gauge boson decaying to a charged lepton and a neutrino in pp collisions at √s=7 TeV JF - The European Physical Journal C N2 - The ATLAS detector at the LHC is used to search for high-mass states, such as heavy charged gauge bosons (W′), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of pp collisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 4.7 fb\(^{−1}\). No excess beyond Standard Model expectations is observed. A W′ with Sequential Standard Model couplings is excluded at the 95 % credibility level for masses up to 2.55 TeV. Excited chiral bosons (W∗) with equivalent coupling strength are excluded for masses up to 2.42 TeV. KW - systematic uncertainty KW - muon decay channel KW - partial decay width KW - simulated signal event KW - background cross section KW - primary vertex KW - sequential standard model KW - muon spectrometer KW - Cl Lowe limit KW - QCD background KW - coupling strength KW - isolation requirement KW - chiral boson KW - experimental systematic uncertainty Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128888 VL - 72 IS - 2241 ER - TY - JOUR T1 - Search for pair production of massive particles decaying into three quarks with the ATLAS detector in √s=7TeV pp collisions at the LHC JF - Journal of High Energy Physics N2 - A search is conducted for hadronic three-body decays of a new massive coloured particle in √s=7TeV pp collisions at the LHC using an integrated luminosity of 4.6 fb\(^{−1}\) collected by the ATLAS detector. Supersymmetric gluino pair production in the context of a model with R-parity violation is used as a benchmark scenario. The analysis is divided into two search channels, each optimised separately for their sensitivity to high-mass and low-mass gluino production. The first search channel uses a stringent selection on the transverse momentum of the six leading jets and is performed as a counting experiment. The second search channel focuses on low-mass gluinos produced with a large boost. Large-radius jets are selected and the invariant mass of each of the two leading jets is used as a discriminant between the signal and the background. The results are found to be consistent with Standard Model expectations and limits are set on the allowed gluino mass. KW - hadron-hadron scattering Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128133 VL - 12 IS - 86 ER - TY - JOUR T1 - Time-dependent angular analysis of the decay B\(^0_s\)→J/ψϕ and extraction of ΔΓ\(_s\) and the CP-violating weak phase ϕ\(_s\) by ATLAS JF - Journal of High Energy Physics N2 - A measurement of B\(^0_s\)→J/ψϕ decay parameters, including the CP -violating weak phase ϕ\(_s\) and the decay width difference ΔΓ\(_s\) is reported, using 4.9 fb\(^{−1}\) of integrated luminosity collected in 2011 by the ATLAS detector from LHC pp collisions at a centre-of-mass energy √s=7 TeV. The mean decay width Γ\(_s\) and the transversity amplitudes |A\(_0\)(0)|\(^2\) and |A\(_∥\)(0)|\(^2\) are also measured. The values reported for these parameters are: ϕ\(_s\)=0.22±0.41 (stat.)±0.10 (syst.) rad ΔΓ\(_s\)=0.053±0.021 (stat.)±0.010 (syst.)ps\(^{−1}\) Γ\(_s\)=0.677±0.007 (stat.)±0.004 (syst.) ps\(^{−1}\) |A\(_0\)(0)|\(^2\)=0.528±0.006 (stat.)±0.009 (syst.) |A\(_∥\)(0)|\(^2\)=0.220±0.008 (stat.)±0.007 (syst.) where the values quoted for ϕ\(_s\) and ΔΓ\(_s\) correspond to the solution compatible with the external measurements to which the strong phase δ\(_⊥\) is constrained and where ΔΓ\(_s\) is constrained to be positive. The fraction of S-wave KK or f\(_0\) contamination through the decays B\(^0_s\)→J/ψK\(^+\)K\(^−\)(f\(_0\)) is measured as well and is found to be consistent with zero. Results for ϕ\(_s\) and ΔΓ\(_s\) are also presented as 68%, 90% and 95% likelihood contours, which show agreement with Standard Model expectations. KW - hadron-hadron scattering Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128125 VL - 12 IS - 072 ER - TY - JOUR T1 - Measurements of the pseudorapidity dependence of the total transverse energy in proton-proton collisions at √s=7 TeV with ATLAS JF - Journal of High Energy Physics N2 - This paper describes measurements of the sum of the transverse energy of particles as a function of particle pseudorapidity, η, in proton-proton collisions at a centre-of-mass energy, √s=7 TeV using the ATLAS detector at the Large Hadron Collider. The measurements are performed in the region |η| < 4.8 for two event classes: those requiring the presence of particles with a low transverse momentum and those requiring particles with a significant transverse momentum. In the second dataset measurements are made in the region transverse to the hard scatter. The distributions are compared to the predictions of various Monte Carlo event generators, which generally tend to underestimate the amount of transverse energy at high |η|. KW - hadron-hadron scattering Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127998 VL - 11 IS - 033 ER - TY - JOUR T1 - Search for anomalous production of prompt like-sign lepton pairs at √s=7TeV with the ATLAS detector JF - Journal of High Energy Physics N2 - An inclusive search for anomalous production of two prompt, isolated leptons with the same electric charge is presented. The search is performed in a data sample corresponding to 4.7 fb\(^{−1}\) of integrated luminosity collected in 2011 at √s=7TeV with the ATLAS detector at the LHC. Pairs of leptons (e\(^{±}\)e\(^{±}\), e\(^{±}\)μ\(^{±}\), and μ\(^{±}\)μ\(^{±}\)) with large transverse momentum are selected, and the dilepton invariant mass distribution is examined for any deviation from the Standard Model expectation. No excess is found, and upper limits on the production cross section of like-sign lepton pairs from physics processes beyond the Standard Model are placed as a function of the dilepton invariant mass within a fiducial region close to the experimental selection criteria. The 95% confidence level upper limits on the cross section of anomalous e\(^{±}\)e\(^{±}\), e\(^{±}\)μ\(^{±}\), or μ\(^{±}\)μ\(^{±}\) production range between 1.7 fb and 64 fb depending on the dilepton mass and flavour combination. KW - hadron-hadron scattering Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127983 VL - 12 IS - 7 ER - TY - JOUR T1 - Search for high-mass resonances decaying to dilepton final states in pp collisions at √s=7 TeV with the ATLAS detector JF - Journal of High Energy Physics N2 - The ATLAS detector at the Large Hadron Collider is used to search for high-mass resonances decaying to an electron-positron pair or a muon-antimuon pair. The search is sensitive to heavy neutral Z′ gauge bosons, Randall-Sundrum gravitons, Z* bosons, techni-mesons, Kaluza-Klein Z/γ bosons, and bosons predicted by Torsion models. Results are presented based on an analysis of pp collisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 4.9 fb\(^{−1}\) in the e\(^+\)e\(^−\) channel and 5.0 fb\(^{−1}\) in the μ\(^+\)μ\(^−\)channel. A Z′ boson with Standard Model-like couplings is excluded at 95 % confidence level for masses below 2.22 TeV. A Randall-Sundrum graviton with coupling k/\(\overline M_{Pl}\)=0.1 is excluded at 95 % confidence level for masses below 2.16 TeV. Limits on the other models are also presented, including Technicolor and Minimal Z′ Models. KW - hadron-hadron scattering Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127974 VL - 11 IS - 138 ER - TY - JOUR T1 - Measurement of W\(^{±}\)Z production in proton-proton collisions at √s=7 TeV with the ATLAS detector JF - European Physical Journal C N2 - 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. KW - ATLAS Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127963 VL - 72 IS - 2173 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 event shapes at large momentum transfer with the ATLAS detector in pp collisions at √s=7 TeV JF - The European Physical Journal C N2 - A measurement of event shape variables is presented for large momentum transfer proton-proton collisions using the ATLAS detector at the Large Hadron Collider. Six event shape variables calculated using hadronic jets are studied in inclusive multi-jet events in 35 pb\(^{−1}\) of integrated luminosity at a center-of-mass energy of √s=7 TeV. These measurements are compared to predictions by three Monte Carlo event generators containing leading-logarithmic parton showers matched to leading order matrix elements for 2→2 and 2→n (n=2,…,6) scattering. Measurements of the third-jet resolution parameter, aplanarity, thrust, sphericity, and transverse sphericity are generally well described. The mean value of each event shape variable is evaluated as a function of the average momentum of the two leading jets p\(_{T,1}\) and p\(_{T,2}\), with a mean p\(_T\) approaching 1 TeV. KW - JES uncertainty KW - event shape variable KW - jet energy scale KW - event shape observable KW - jet cross section KW - high jet multiplicity KW - jet calibration KW - parton shower KW - energy scale KW - MC program KW - hadronic final state KW - jet transverse momentum KW - MC event generator KW - systematic uncertainty Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127813 VL - 72 IS - 2211 ER - 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 - Search for anomaly-mediated supersymmetry breaking with the ATLAS detector based on a disappearing-track signature in pp collisions at √s=7 TeV JF - The European Physical Journal C N2 - 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. KW - chargino decay KW - anomaly mediation KW - supersymmetry KW - symmetry breaking KW - scattering KW - chargino lifetime KW - sparticle cascade decay KW - chargino mass KW - track data analysis KW - transverse momentum momentum spectrum KW - background KW - Monte Carlo KW - experimental results KW - sparticle pair production KW - chargino --> neutralino pi KW - CERN LHC Coll KW - ATLAS KW - 7000 GeV-cms Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127850 VL - 72 IS - 1993 ER - TY - JOUR T1 - Search for heavy neutrinos and right-handed W bosons in events with two leptons and jets in pp collisions at \(\sqrt{s}\)=7TeV with the ATLAS detector JF - The European Physical Journal C N2 - This letter reports on a search for hypothetical heavy neutrinos, N, and right-handed gauge bosons, W R, in events with high transverse momentum objects which include two reconstructed leptons and at least one hadronic jet. The results were obtained from data corresponding to an integrated luminosity of 2.1 fb\(^{−1}\) collected in proton–proton collisions at √s=7 TeV with the ATLAS detector at the CERN Large Hadron Collider. No excess above the Standard Model background expectation is observed. Excluded mass regions for Majorana and Dirac neutrinos are presented using two approaches for interactions that violate lepton and lepton-flavor numbers. One approach uses an effective operator framework, the other approach is guided by the Left–Right Symmetric Model. The results described in this letter represent the most stringent limits to date on the masses of heavy neutrinos and W\(_R\) bosons obtained in direct searches. KW - dilepton invariant mass, KW - heavy neutrino KW - non-prompt lepton KW - Anti-k Jet KW - fake lepton Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127796 VL - 72 IS - 2056 ER - TY - JOUR T1 - Search for lepton flavour violation in the eμ continuum with the ATLAS detector in √s=7 TeV pp collisions at the LHC JF - The European Physical Journal C N2 - This paper presents a search for the t-channel exchange of an R-parity violating scalar top quark ( \(\tilde{t}\) ) in the e\(^±\) μ\(^∓\) continuum using 2.1 fb\(^{−1}\) of data collected by the ATLAS detector in √s=7 TeV pp collisions at the Large Hadron Collider. Data are found to be consistent with the expectation from the Standard Model backgrounds. Limits on R-parity-violating couplings at 95 % C.L. are calculated as a function of the scalar top mass (m\(_\tilde{t}\)). The upper limits on the production cross section for pp→eμX, through the t-channel exchange of a scalar top quark, ranges from 170 fb for m\(_\tilde{t}\)=95 GeV to 30 fb for m\(_\tilde{t}\)=1000 GeV. KW - Large Hadron Collider KW - Pp Collision KW - Atlas detector KW - top quark KW - production cross section Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127632 VL - 72 IS - 2040 ER - TY - JOUR T1 - Rapidity gap cross sections measured with the ATLAS detector in pp collisions at √s=7TeV JF - The European Physical Journal C N2 - Pseudorapidity gap distributions in proton-proton collisions at √s=7 TeV are studied using a minimum bias data sample with an integrated luminosity of 7.1 μb\(^{−1}\). Cross sections are measured differentially in terms of Δη\(^F\), the larger of the pseudorapidity regions extending to the limits of the ATLAS sensitivity, at η=±4.9, in which no final state particles are produced above a transverse momentum threshold pcutT. The measurements span the region 0<Δη\(^F\)<8 for 200MeV50 GeV. Good agreement is found with theoretical predictions. For p\(^W_T\)>50 GeV, the values of f\(_0\) and f\(_L\)−f\(_R\), averaged over charge and lepton flavour, are measured to be: f\(_0\)=0.127±0.030±0.108 and f\(_L\)−f\(_R\)=0.252±0.017±0.030, where the first uncertainties are statistical, and the second include all systematic effects. KW - good agreement KW - transverse plane KW - Atlas detector KW - transverse momentum KW - helicity fraction KW - Pp Collision KW - lepton flavour KW - systematic effect Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127615 VL - 72 IS - 2001 ER - TY - JOUR T1 - Performance of missing transverse momentum reconstruction in proton-proton collisions at √s=7 TeV with ATLAS JF - The European Physical Journal C N2 - The measurement of missing transverse momentum in the ATLAS detector, described in this paper, makes use of the full event reconstruction and a calibration based on reconstructed physics objects. The performance of the missing transverse momentum reconstruction is evaluated using data collected in pp collisions at a centre-of-mass energy of 7 TeV in 2010. Minimum bias events and events with jets of hadrons are used from data samples corresponding to an integrated luminosity of about 0.3 nb\(^{−1}\) and 600 nb\(^{−1}\) respectively, together with events containing a Z boson decaying to two leptons (electrons or muons) or a W boson decaying to a lepton (electron or muon) and a neutrino, from a data sample corresponding to an integrated luminosity of about 36 pb\(^{−1}\). An estimate of the systematic uncertainty on the missing transverse momentum scale is presented KW - momentum scale KW - Atlas detector KW - pp collision KW - systematic uncertainty KW - transverse momentum Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127530 VL - 72 IS - 1844 ER - TY - JOUR T1 - Search for top and bottom squarks from gluino pair production in final states with missing transverse energy and at least three b-jets with the ATLAS detector JF - The European Physical Journal C N2 - This letter reports the results of a search for top and bottom squarks from gluino pair production in 4.7 fb\(^{−1}\) of pp collisions at √s=7 TeV using the ATLAS detector at the LHC. The search is performed in events with large missing transverse momentum and at least three jets identified as originating from a b-quark. Exclusion limits are presented for a variety of gluino-mediated models with gluino masses up to 1 TeV excluded. KW - SM Background KW - jet response KW - direct pair production KW - visible cross section KW - jet energy scale KW - Anti-k Jet KW - PDF set KW - validation region Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127523 VL - 72 IS - 2174 ER - TY - JOUR T1 - Search for a heavy top-quark partner in final states with two leptons with the ATLAS detector at the LHC JF - Journal of High Energy Physics N2 - The results of a search for direct pair production of heavy top-quark partners in 4.7 fb\(^{−1}\) of integrated luminosity from pp collisions at √s=7 TeV collected by the ATLAS detector at the LHC are reported. Heavy top-quark partners decaying into a top quark and a neutral non-interacting particle are searched for in events with two leptons in the final state. No excess above the Standard Model expectation is observed. Limits are placed on the mass of a supersymmetric scalar top and of a spin-1/2 top-quark partner. A spin-1/2 top-quark partner with a mass between 300 GeV and 480 GeV, decaying to a top quark and a neutral non-interacting particle lighter than 100 GeV, is excluded at 95% confidence level. KW - hadron-hadron scattering Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127511 VL - 11 IS - 094 ER - TY - JOUR T1 - Search for a fermiophobic Higgs boson in the diphoton decay channel with the ATLAS detector JF - The European Physical Journal C N2 - A search for a fermiophobic Higgs boson using diphoton events produced in proton-proton collisions at a centre-of-mass energy of √s=7 TeV is performed using data corresponding to an integrated luminosity of 4.9 fb\(^{−1}\) collected by the ATLAS experiment at the Large Hadron Collider. A specific benchmark model is considered where all the fermion couplings to the Higgs boson are set to zero and the bosonic couplings are kept at the Standard Model values (fermiophobic Higgs model). The largest excess with respect to the background-only hypothesis is found at 125.5 GeV, with a local significance of 2.9 standard deviations, which reduces to 1.6 standard deviations when taking into account the look-elsewhere effect. The data exclude the fermiophobic Higgs model in the ranges 110.0–118.0 GeV and 119.5–121.0 GeV at 95 % confidence level. KW - unconverted photon KW - Higgs boson signal KW - photon energy scale KW - invariant mass resolution KW - diphoton invariant mass Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127427 VL - 72 IS - 2157 ER - TY - JOUR T1 - Measurement of the W boson polarization in top quark decays with the ATLAS detector JF - Journal of High Energy Physics N2 - This paper presents measurements of the polarization of W bosons in top quark decays, derived from \(t\overline{t}\) events with missing transverse momentum, one charged lepton and at least four jets, or two charged leptons and at least two jets. Data from pp collisions at a centre-of-mass energy of 7 TeV were collected with the ATLAS experiment at the LHC and correspond to an integrated luminosity of 1.04 fb\(^{−1}\). The measured fractions of longitudinally, left- and right-handed polarization are F\(_0\) = 0.67 ± 0.07, F\(_L\) = 0.32 ± 0.04 and F\(_R\) = 0.01 ± 0.05, in agreement with the Standard Model predictions. As the polarization of the W bosons in top quark decays is sensitive to the Wtb vertex Lorentz structure and couplings, the measurements were used to set limits on anomalous contributions to the Wtb couplings. KW - hadron-hadron scattering Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127417 VL - 06 IS - 88 ER - TY - JOUR T1 - Measurement of inclusive two-particle angular correlations in pp collisions with the ATLAS detector at the LHC JF - Journal of High Energy Physics N2 - We present a measurement of two-particle angular correlations in proton- proton collisions at √s=900 GeV and 7 TeV. The collision events were collected during 2009 and 2010 with the ATLAS detector at the Large Hadron Collider using a single-arm minimum bias trigger. Correlations are measured for charged particles produced in the kinematic range of transverse momentum p\(_T\)  > 100 MeV and pseudorapidity |η| < 2.5. A complex structure in pseudorapidity and azimuth is observed at both collision energies. Results are compared to PYTHIA 8 and HERWIG++ as well as to the AMBT2B, DW and Perugia 2011 tunes of PYTHIA 6. The data are not satisfactorily described by any of these models. KW - hadron-hadron scattering Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127350 VL - 05 IS - 157 ER - TY - THES A1 - Mautner, Romana T1 - Datenintegration für Bauprojekte der Gebietskörperschaften T1 - Integration of data for construction projects of territorial authorities N2 - Bei der Durchführung öffentlicher Bauprojekte ist eine intensive Zusammenarbeit zwi¬schen vielen Beteiligten erforderlich: die in der Bauverwaltung des Bauherren angesiedelte Projektleitung, Bedarfsträger (z. B. Universität oder Be¬hörde), Gre-mien des Bauherrn (Kommunal-, Kreis- oder Bundesparlament), dessen Haus-haltsabteilung, Objekt- und Fachplaner (freiberuflich oder als Mitarbeiter der Bauverwaltung), Gutachter, Bauunternehmen, Lieferanten und Dienstleister, Raumordnungs-, Planfeststellungs- und Genehmigungsbehörden. Der Planungs-, Genehmigungs- und Realisationsprozess erstreckt sich meist über mehrere Jahre. Währenddessen ist ein intensiver Informations- und Kommunikationsaustausch zwischen den Beteiligten erforderlich. Baupläne, Leistungsverzeichnisse, Ange-bote, Verträge, Protokolle, Bauzeitenpläne und Rechnungen werden immer noch per E-Mail oder in Papierform ausgetauscht. Wegen der meist größeren Zahl zeit-gleich betreuter Bauprojekte führt dies bei fast allen Beteiligten regelmäßig zu einer herausfordernd großen Korrespondenz und einem als mangelhaft zu be-zeichnenden Überblick über die aktuellen Projektdaten. Wegen der hochgradigen Interdependenz der Teilprozesse über alle Phasen hin-weg sind aber eine möglichst reibungslose Koordination und die ständige Verfüg-barkeit aktueller Daten bei allen Beteiligten unabdingbare Voraussetzungen, um eine Baumaßnahme zügig und im vorgesehenen Kostenrahmen auszuführen. Während Datenaustausch und Koordination bei großen gewerblichen Bauprojek-ten bereits mit Erfolg durch virtuelle Projekträume unterstützt werden, sind die öffentlichen Bauverwaltungen hier noch zögerlich. Die Erstellung eines einheitli-chen und prozessübergreifenden Datenmodells speziell für die Abläufe öffentli-cher Auftraggeber als Ziel der Arbeit könnte helfen, die Vorteile eines zentralen, für alle Beteiligten zugänglichen Datenbestandes auch für die Bauverwaltungen und ihre Projekte nutzbar zu machen und vormals getrennt gehaltene Datenbe-stände zu einem einzigen zusammenzuführen (Datenintegration). Die gründliche Analyse der Abläufe und Informationsflüsse zwischen den Beteiligten über alle Phasen eines öffentlichen Bauprojekts hinweg sowie eine Bestandsaufnahme der gegenwärtig am Markt verfügbaren virtuellen Projekträume im ersten Teil der Arbeit bilden die Grundlage für die Modellierung der Daten sowie ihrer Zusam-menhänge im zweiten Teil. Mit der Gesamtdarstellung der Beteiligten, ihrer Rollen und Aufgaben, der Do-kumente und der zugehörigen Metadaten über alle Phasen und Baufachbereiche hinweg wurde ein neuer Forschungsbeitrag erarbeitet. Die unterschiedlichen Be-zeichnungen z. B. in Hoch- und Tiefbauprojekten wurden im Interesse der Ver-ständlichkeit erhalten, aber in einer gemeinsamen Struktur zusammengeführt. Diese Modellierung ist die Voraussetzung für eine verbesserte informationstech-nische Unterstützung öffentlicher Bauprojekte und zugleich die ureigenste Aufga-be des Wirtschaftsinformatikers als Mittler zwischen Anwendern und Entwick-lern. Das in dieser Arbeit entwickelte Datenmodell erlaubt wegen seiner verwaltungs- und baufachbereichsübergreifenden Konzeption im Sinne eines Referenzmodells den Einsatz als Basis einer Standardanwendungssoftware, die mit geringem An-passungsaufwand bei einer großen Zahl an Kunden im öffentlichen Bereich einge-setzt werden kann. Beispiele sind Projektraumanwendungen sowie Workflow-Management-Systeme. Es ist zugleich ein Referenzvorschlag an die Entwickler bestehender Anwendungen zur Definition von Schnittstellen und schließlich zur Umsetzung applikationsübergreifender Integrationsansätze. N2 - Public financed construction projects require an intensive collaboration between a large number of involved parties: the project management (done by the building authority), the demand carrier (for example a university or authority), the builder-owner’s panel (local, city or county council, parliament), its financial department, the architect, planners and designers (as freelancers or employees of the building authority), assessors, construction companies, suppliers and service providers, autho¬rities for comprehensive regional planning and planning approval. Usually, the process of planning, its approval and realization takes several years. Mean-while, a close exchange of information between these involved parties is essential. Construction plans, specifications sheets, offers, treaties, minutes, time schedules and invoices are still forwarded by e-mail or as hardcopy. The results are over-crowded inboxes and an impaired overview of project data, because most parties are involved in multiple complex projects. For finishing a construction project in time and at estimated cost frictionless coor-dination and all-time availability of current data are essential, especially because of the high-level interdependency of all sub processes. In large commercial con-struction projects this is countenanced by virtual project rooms already, but au-thorities still tarry. They should step on and take advantage of a central database. The creation of a standardised and cross-process data model is useful especially for processes of public sector. The advantages of central data, accessible for all authorised parties, are forcing all participants of a construction project to integrate formerly separated databases into one (data integration). An in-depth analysis of the information flow during the whole process of a public construction project as well as an examination of the currently available virtual project room solutions in the first part of the dissertation are providing the foundation for data modelling in the second part. The created overall view of involved parties, their roles and tasks, the documents and its meta data throughout the entire process and for all construction areas is unique and a new scientific approach. The dissertation kept the different structur-al designations of underground engineering and high-building projects to ensure understanding but includes a common framework model. The created model is the precondition for an improved IT support of public construction projects, and being the mediator bet¬ween clients and developers is the classical task for business in-formatics. The model created in this dissertation isn’t fitted to a special construction field neither to a specific local, city or county. Therefore, it can be used as a reference model in standard application software. Being implemented as the foundation for such a software it would only take adaption work to be applied at many public customers, for instance in project rooms solutions or workflow management sys-tems. The data framework is a recommendation, a reference model to developers for the implementation of interfaces for existing applications, and can foster cross-application integration. KW - Bauvorhaben KW - Datenintegration KW - Öffentliche Bauprojekte KW - Öffentlicher Sektor KW - Datenmanagement KW - Bauprojekt Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-138611 ER - TY - JOUR A1 - Aad, G. A1 - Abbott, B. A1 - Abdallah, J. A1 - Abdelalim, A. A. A1 - Abdesselam, A. T1 - Forward-backward correlations and charged-particle azimuthal distributions in pp interactions using the ATLAS detector JF - Journal of High Energy Physics N2 - Using inelastic proton-proton interactions at s√=900 GeV and 7 TeV, recorded by the ATLAS detector at the LHC, measurements have been made of the correlations between forward and backward charged-particle multiplicities and, for the first time, between forward and backward charged-particle summed transverse momentum. In addition, jet-like structure in the events is studied by means of azimuthal distributions of charged particles relative to the charged particle with highest transverse momentum in a selected kinematic region of the event. The results are compared with predictions from tunes of the pythia and herwig++ Monte Carlo generators, which in most cases are found to provide a reasonable description of the data. KW - Hadron-Hadron Scattering Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127336 VL - 7 IS - 19 ER - TY - JOUR A1 - Aad, G. A1 - Abbott, B. A1 - Abdallah, J. A1 - Abdelalim, A. A. A1 - Abdesselam, A. T1 - Performance of the ATLAS Trigger System in 2010 JF - The European Physical Journal C N2 - 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. KW - ATLAS KW - Trigger System Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127321 VL - 72 IS - 1849 ER - TY - JOUR A1 - Aad, G. A1 - Abbott, B. A1 - Abdallah, J. A1 - Abdelalim, A. A. A1 - Abdesselam, A. T1 - Electron performance measurements with the ATLAS detector using the 2010 LHC proton-proton collision data JF - The European Physical Journal C N2 - Detailed measurements of the electron performance of the ATLAS detector at the LHC are reported, using decays of the Z, W and J/ψ particles. Data collected in 2010 at s√=7 TeV are used, corresponding to an integrated luminosity of almost 40 pb\(^{−1}\). The inter-alignment of the inner detector and the electromagnetic calorimeter, the determination of the electron energy scale and resolution, and the performance in terms of response uniformity and linearity are discussed. The electron identification, reconstruction and trigger efficiencies, as well as the charge misidentification probability, are also presented. KW - electromagnetic calorimeter KW - Atlas detector KW - calorimeter Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127313 VL - 72 IS - 1909 ER - TY - JOUR A1 - Aad, G. A1 - Abbott, B. A1 - Abdallah, J. A1 - Abdel Khalek, S. A1 - Abdelalim, A. A. T1 - 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 JF - Physics Letters B N2 - 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. KW - ATLAS KW - LHC KW - Higgs KW - WW Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127307 VL - 761 IS - 1 ER - TY - JOUR A1 - Jahn, Daniel A1 - Schramm, Sabine A1 - Schnölzer, Martina A1 - Heilmann, Clemens J. A1 - de Koster, Chris G. A1 - Schütz, Wolfgang A1 - Benavente, Ricardo A1 - Alsheimer, Manfred T1 - A truncated lamin A in the Lmna\(^{−/−}\) mouse line: Implications for the understanding of laminopathies JF - Nucleus N2 - During recent years a number of severe clinical syndromes, collectively termed laminopathies, turned out to be caused by various, distinct mutations in the human LMNA gene. Arising from this, remarkable progress has been made to unravel the molecular pathophysiology underlying these disorders. A great benefit in this context was the generation of an A-type lamin deficient mouse line (Lmna\(^{−/−}\)) by Sullivan and others,1 which has become one of the most frequently used models in the field and provided profound insights to many different aspects of A-type lamin function. Here, we report the unexpected finding that these mice express a truncated Lmna gene product on both transcriptional and protein level. Combining different approaches including mass spectrometry, we precisely define this product as a C-terminally truncated lamin A mutant that lacks domains important for protein interactions and post-translational processing. Based on our findings we discuss implications for the interpretation of previous studies using Lmna\(^{−/−}\) mice and the concept of human laminopathies. KW - nuclear organization KW - A-type lamins KW - LMNA mutations KW - laminopathies KW - nuclear envelope KW - nuclear lamina Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127281 VL - 3 IS - 5 ER - TY - JOUR A1 - Klotz, Barbara A1 - Mentrup, Birgit A1 - Regensburger, Martina A1 - Zeck, Sabine A1 - Schneidereit, Jutta A1 - Schupp, Nicole A1 - Linden, Christian A1 - Merz, Cornelia A1 - Ebert, Regina A1 - Jakob, Franz T1 - 1,25-Dihydroxyvitamin D3 Treatment Delays Cellular Aging in Human Mesenchymal Stem Cells while Maintaining Their Multipotent Capacity JF - PLoS ONE N2 - 1,25-dihydroxyvitamin D3 (1,25D3) was reported to induce premature organismal aging in fibroblast growth factor-23 (Fgf23) and klotho deficient mice, which is of main interest as 1,25D3 supplementation of its precursor cholecalciferol is used in basic osteoporosis treatment. We wanted to know if 1,25D3 is able to modulate aging processes on a cellular level in human mesenchymal stem cells (hMSC). Effects of 100 nM 1,25D3 on hMSC were analyzed by cell proliferation and apoptosis assay, beta-galactosidase staining, VDR and surface marker immunocytochemistry, RT-PCR of 1,25D3-responsive, quiescence-and replicative senescence-associated genes. 1,25D3 treatment significantly inhibited hMSC proliferation and apoptosis after 72 h and delayed the development of replicative senescence in long-term cultures according to beta-galactosidase staining and P16 expression. Cell morphology changed from a fibroblast like appearance to broad and rounded shapes. Long term treatment did not induce lineage commitment in terms of osteogenic pathways but maintained their clonogenic capacity, their surface marker characteristics (expression of CD73, CD90, CD105) and their multipotency to develop towards the chondrogenic, adipogenic and osteogenic pathways. In conclusion, 1,25D3 delays replicative senescence in primary hMSC while the pro-aging effects seen in mouse models might mainly be due to elevated systemic phosphate levels, which propagate organismal aging. KW - perspectives KW - bone marrow KW - mutant mice KW - oxidative stress KW - transcription factors KW - vitamin-D-receptor KW - differentiation KW - tissue KW - 2',7'-dichlorofluorescin KW - homeostasis Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-133392 VL - 7 IS - 1 ER - TY - JOUR A1 - Nono, Justin Komguep A1 - Pletinckx, Katrien A1 - Lutz, Manfred B. A1 - Brehm, Klaus T1 - Excretory/Secretory-Products of Echinococcus multilocularis Larvae Induce Apoptosis and Tolerogenic Properties in Dendritic Cells In Vitro JF - PLoS Neglected Tropical Diseases N2 - Background: Alveolar echinococcosis, caused by Echinococcus multilocularis larvae, is a chronic disease associated with considerable modulation of the host immune response. Dendritic cells (DC) are key effectors in shaping the immune response and among the first cells encountered by the parasite during an infection. Although it is assumed that E. multilocularis, by excretory/secretory (E/S)-products, specifically affects DC to deviate immune responses, little information is available on the molecular nature of respective E/S-products and their mode of action. Methodology/Principal Findings: We established cultivation systems for exposing DC to live material from early (oncosphere), chronic (metacestode) and late (protoscolex) infectious stages. When co-incubated with Echinococcus primary cells, representing the invading oncosphere, or metacestode vesicles, a significant proportion of DC underwent apoptosis and the surviving DC failed to mature. In contrast, DC exposed to protoscoleces upregulated maturation markers and did not undergo apoptosis. After pre-incubation with primary cells and metacestode vesicles, DC showed a strongly impaired ability to be activated by the TLR ligand LPS, which was not observed in DC pre-treated with protoscolex E/S-products. While none of the larvae induced the secretion of pro-inflammatory IL-12p70, the production of immunosuppressive IL-10 was elevated in response to primary cell E/S-products. Finally, upon incubation with DC and naive T-cells, E/S-products from metacestode vesicles led to a significant expansion of Foxp3+ T cells in vitro. Conclusions: This is the first report on the induction of apoptosis in DC by cestode E/S-products. Our data indicate that the early infective stage of E. multilocularis is a strong inducer of tolerance in DC, which is most probably important for generating an immunosuppressive environment at an infection phase in which the parasite is highly vulnerable to host attacks. The induction of CD4+CD25+Foxp3+ T cells through metacestode E/S-products suggests that these cells fulfill an important role for parasite persistence during chronic echinococcosis. KW - granulosus KW - hydatid disease KW - metacestode vesicles KW - antigen-B KW - alveoar echinococcosis KW - TGF-BETA KW - regulatory T cells KW - gene expression KW - Brugia Malayi KW - TNF-alpha Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-134280 VL - 6 IS - 2 ER - TY - JOUR A1 - Fröhlich, Kathrin S. A1 - Papenfort, Kai A1 - Berger, Allison A. A1 - Vogel, Jörg T1 - A conserved RpoS-dependent small RNA controls the synthesis of major porin OmpD JF - Nucleic Acids Research N2 - A remarkable feature of many small non-coding RNAs (sRNAs) of Escherichia coli and Salmonella is their accumulation in the stationary phase of bacterial growth. Several stress response regulators and sigma factors have been reported to direct the transcription of stationary phase-specific sRNAs, but a widely conserved sRNA gene that is controlled by the major stationary phase and stress sigma factor, Sigma(S) (RpoS), has remained elusive. We have studied in Salmonella the conserved SdsR sRNA, previously known as RyeB, one of the most abundant stationary phase-specific sRNAs in E. coli. Alignments of the sdsR promoter region and genetic analysis strongly suggest that this sRNA gene is selectively transcribed by Sigma(S). We show that SdsR down-regulates the synthesis of the major Salmonella porin OmpD by Hfq-dependent base pairing; SdsR thus represents the fourth sRNA to regulate this major outer membrane porin. Similar to the InvR, MicC and RybB sRNAs, SdsR recognizes the ompD mRNA in the coding sequence, suggesting that this mRNA may be primarily targeted downstream of the start codon. The SdsR-binding site in ompD was localized by 3'-RACE, an experimental approach that promises to be of use in predicting other sRNA-target interactions in bacteria. KW - shock sigma factor KW - general stress response KW - down regulation KW - stationary phase KW - salmonella enterica KW - messenger RNA KW - escherichia coli KW - enterica serovar typhimurium KW - outer-membrane proteins KW - small noncoding RNAs Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-134230 VL - 40 IS - 8 ER - TY - JOUR A1 - Makoah Nigel, Animake A1 - Arndt, Hans-Dieter A1 - Pradel, Gabriele T1 - The proteasome of malaria parasites: A multi-stage drug target for chemotherapeutic intervention? JF - International Journal for Parasitology: Drugs and Drug Resistance N2 - The ubiquitin/proteasome system serves as a regulated protein degradation pathway in eukaryotes, and is involved in many cellular processes featuring high protein turnover rates, such as cell cycle control, stress response and signal transduction. In malaria parasites, protein quality control is potentially important because of the high replication rate and the rapid transformations of the parasite during life cycle progression. The proteasome is the core of the degradation pathway, and is a major proteolytic complex responsible for the degradation and recycling of non-functional ubiquitinated proteins. Annotation of the genome for Plasmodium falciparum, the causative agent of malaria tropica, revealed proteins with similarity to human 26S proteasome subunits. In addition, a bacterial ClpQ/hslV threonine peptidase-like protein was identified. In recent years several independent studies indicated an essential function of the parasite proteasome for the liver, blood and transmission stages. In this review, we compile evidence for protein recycling in Plasmodium parasites and discuss the role of the 26S proteasome as a prospective multi-stage target for antimalarial drug discovery programs. KW - plasmodium falciparum KW - proteasome KW - ubiquitin KW - inhibitor Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-137777 VL - 2 ER - TY - JOUR A1 - Schubert, Maria A1 - Joniau, Steven A1 - Gontero, Paolo A1 - Kneitz, Susanne A1 - Scholz, Claus-Jürgen A1 - Kneitz, Burkhard A1 - Briganti, Alberto A1 - Karnes, R. Jeffery A1 - Tombal, Bertrand A1 - Walz, Jochen A1 - Hsu, Chao-Yu A1 - Marchioro, Giansilvio A1 - Bader, Pia A1 - Bangma, Chris A1 - Frohneberg, Detlef A1 - Graefen, Markus A1 - Schröder, Fritz A1 - van Cangh, Paul A1 - van Poppel, Hein A1 - Spahn, Martin T1 - The Role of Adjuvant Hormonal Treatment after Surgery for Localized High-Risk Prostate Cancer: Results of a Matched Multiinstitutional Analysis JF - Advances in Urology N2 - Introduction. To assess the role of adjuvant androgen deprivation therapy (ADT) in high-risk prostate cancer patients (PCa) after surgery. Materials and Methods. The analysis case matched 172 high-risk PCa patients with positive section margins or non-organ confined disease and negative lymph nodes to receive adjuvant ADT (group 1, n=86 ) or no adjuvant ADT (group 2, n=86). Results. Only 11.6% of the patients died, 2.3% PCa related. Estimated 5–10-year clinical progression-free survival was 96.9% (94.3%) for group 1 and 73.7% (67.0%) for group 2, respectively. Subgroup analysis identified men with T2/T3a tumors at low-risk and T3b margins positive disease at higher risk for progression. Conclusion. Patients with T2/T3a tumors are at low-risk for metastatic disease and cancer-related death and do not need adjuvant ADT. We identified men with T3b margin positive disease at highest risk for clinical progression. These patients benefit from immediate adjuvant ADT. KW - prostate cancer KW - adjuvant hormonal treatment Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-137712 VL - 2012 ER - TY - JOUR A1 - Lioliou, Efthimia A1 - Sharma, Cynthia M. A1 - Caldelari, Isabelle A1 - Helfer, Anne-Catherine A1 - Fechter, Pierre A1 - Vandenesch, François A1 - Vogel, Jörg A1 - Romby, Pascale T1 - Global Regulatory Functions of the Staphylococcus aureus Endoribonuclease III in Gene Expression JF - PLoS Genetics N2 - RNA turnover plays an important role in both virulence and adaptation to stress in the Gram-positive human pathogen Staphylococcus aureus. However, the molecular players and mechanisms involved in these processes are poorly understood. Here, we explored the functions of S. aureus endoribonuclease III (RNase III), a member of the ubiquitous family of double-strand-specific endoribonucleases. To define genomic transcripts that are bound and processed by RNase III, we performed deep sequencing on cDNA libraries generated from RNAs that were co-immunoprecipitated with wild-type RNase III or two different cleavage-defective mutant variants in vivo. Several newly identified RNase III targets were validated by independent experimental methods. We identified various classes of structured RNAs as RNase III substrates and demonstrated that this enzyme is involved in the maturation of rRNAs and tRNAs, regulates the turnover of mRNAs and non-coding RNAs, and autoregulates its synthesis by cleaving within the coding region of its own mRNA. Moreover, we identified a positive effect of RNase III on protein synthesis based on novel mechanisms. RNase III–mediated cleavage in the 5′ untranslated region (5′UTR) enhanced the stability and translation of cspA mRNA, which encodes the major cold-shock protein. Furthermore, RNase III cleaved overlapping 5′UTRs of divergently transcribed genes to generate leaderless mRNAs, which constitutes a novel way to co-regulate neighboring genes. In agreement with recent findings, low abundance antisense RNAs covering 44% of the annotated genes were captured by co-immunoprecipitation with RNase III mutant proteins. Thus, in addition to gene regulation, RNase III is associated with RNA quality control of pervasive transcription. Overall, this study illustrates the complexity of post-transcriptional regulation mediated by RNase III. KW - staphylococcus aureus KW - ribonucleases KW - messenger RNA KW - RNA sequencing KW - antisense RNA KW - RNA structure KW - RNA synthesis KW - RNA denaturation Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127219 VL - 8 IS - 6 ER - TY - JOUR A1 - Rakosy, Demetra A1 - Streinzer, Martin A1 - Paulus, Hannes F. A1 - Spaethe, Johannes T1 - Floral visual signal increases reproductive success in a sexually deceptive orchid JF - Arthropod-Plant Interactions N2 - Sexually deceptive orchids mimic signals emitted by female insects in order to attract mate-searching males. Specific attraction of the targeted pollinator is achieved by sex pheromone mimicry, which constitutes the major attraction channel. In close vicinity of the flower, visual signals may enhance attraction, as was shown recently in the sexually deceptive orchid Ophrys heldreichii. Here, we conducted an in situ manipulation experiment in two populations of O. heldreichii on Crete to investigate whether the presence/absence of the conspicuous pink perianth affects reproductive success in two natural orchid populations. We estimated reproductive success of three treatment groups (with intact, removed and artificial perianth) throughout the flowering period as pollinaria removal (male reproductive success) and massulae deposition (female reproductive success). Reproductive success was significantly increased by the presence of a strong visual signal—the conspicuous perianth—in one study population, however, not in the second, most likely due to the low pollinator abundance in the latter population. This study provides further evidence that the coloured perianth in O. heldreichii is adaptive and thus adds to the olfactory signal to maximise pollinator attraction and reproductive success. KW - sexual deception KW - eucera berlandi KW - male bees KW - ophrys heldreichii KW - pollination Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127209 VL - 6 IS - 4 ER - TY - JOUR A1 - Wilms, Ina A1 - Overlöper, Aaron A1 - Nowrousian, Minou A1 - Sharma, Cynthia M. A1 - Narberhaus, Franz T1 - Deep sequencing uncovers numerous small RNAs on all four replicons of the plant pathogen Agrobacterium tumefaciens JF - RNA Biology N2 - Agrobacterium species are capable of interkingdom gene transfer between bacteria and plants. The genome of Agrobacterium tumefaciens consists of a circular and a linear chromosome, the At-plasmid and the Ti-plasmid, which harbors bacterial virulence genes required for tumor formation in plants. Little is known about promoter sequences and the small RNA (sRNA) repertoire of this and other α-proteobacteria. We used a differential RNA sequencing (dRNA-seq) approach to map transcriptional start sites of 388 annotated genes and operons. In addition, a total number of 228 sRNAs was revealed from all four Agrobacterium replicons. Twenty-two of these were confirmed by independent RNA gel blot analysis and several sRNAs were differentially expressed in response to growth media, growth phase, temperature or pH. One sRNA from the Ti-plasmid was massively induced under virulence conditions. The presence of 76 cis-antisense sRNAs, two of them on the reverse strand of virulence genes, suggests considerable antisense transcription in Agrobacterium. The information gained from this study provides a valuable reservoir for an in-depth understanding of sRNA-mediated regulation of the complex physiology and infection process of Agrobacterium. KW - regulatory RNA KW - plant-microbe interaction KW - deep sequencing KW - RNA-seq KW - small RNA Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127101 VL - 9 IS - 446-457 ER - TY - JOUR A1 - Bonn, Maria A1 - Schmitt, Angelika A1 - Asan, Esther T1 - Double and triple in situ hybridization for coexpression studies: combined fluorescent and chromogenic detection of neuropeptide Y (NPY) and serotonin receptor subtype mRNAs expressed at different abundance levels JF - Histochemistry and Cell Biology N2 - Multiple fluorescence in situ hybridization is the method of choice for studies aimed at determining simultaneous production of signal transduction molecules and neuromodulators in neurons. In our analyses of the monoamine receptor mRNA expression of peptidergic neurons in the rat telencephalon, double tyramide-signal-amplified fluorescence in situ hybridization delivered satisfactory results for coexpression analysis of neuropeptide Y (NPY) and serotonin receptor 2C (5-HT2C) mRNA, a receptor subtype expressed at high-to-moderate abundance in the regions analyzed. However, expression of 5-HT1A mRNA, which is expressed at comparatively low abundance in many telencephalic areas, could not be unequivocally identified in NPY mRNA-reactive neurons due to high background and poor signal-to-noise ratio in fluorescent receptor mRNA detections. Parallel chromogenic in situ hybridization provided clear labeling for 5-HT1A mRNA and additionally offered the possibility to monitor the chromogen deposition at regular time intervals to determine the optimal signal-to-noise ratio. We first developed a double labeling protocol combining fluorescence and chromogenic in situ hybridization and subsequently expanded this variation to combine double fluorescence and chromogenic in situ hybridization for triple labelings. With this method, we documented expression of 5-HT2C and/or 5-HT1A in subpopulations of telencephalic NPY-producing neurons. The method developed in the present study appears suitable for conventional light and fluorescence microscopy, combines advantages of fluorescence and chromogenic in situ hybridization protocols and thus provides a reliable non-radioactive alternative to previously published multiple labeling methods for coexpression analyses in which one mRNA species requires highly sensitive detection. KW - 5-HT1A KW - NPY KW - coexpression KW - triple in situ hybridization KW - 5-HT2C Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127080 VL - 137 IS - 1 ER -