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 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 - 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 -