Abstract
An inclusive search for anomalous production of two prompt, isolated muons with the same electric charge is presented. The search is performed in a data sample corresponding to 1.6 fb^-1 of integrated luminosity collected in 2011 at sqrt(s) = 7 TeV with the ATLAS detector at the LHC. Muon pairs are selected by requiring two isolated muons of the same electric charge with pT > 20 GeV and abs(eta) < 2.5. Minimal requirements are placed on the rest of the event activity. The distribution of the invariant mass of the muon pair m(mumu) is found to agree well with the background expectation. Upper limits on the cross section for anomalous production of two muons with the same electric charge are placed as a function of m(mumu) within a fiducial region defined by the event selection. The fiducial cross- section limit constrains the like-sign top-quark pair-production cross section to be below 3.7 pb at 95% confidence level. The data are also analyzed to search for a narrow like-sign dimuon resonance as predicted for e.g. doubly charged Higgs bosons (H++/H--). Assuming pair production of H++/H-- bosons and a branching ratio to muons of 100% (33%), this analysis excludes masses below 355 (244) GeV and 251 (209) GeV for H++/H-- bosons coupling to left-handed and right-handed fermions, respectively.
Highlights
Events containing two high-pT, prompt, like-sign leptons are rarely produced in the standard model (SM), but occur with an enhanced rate in several models of new physics
In the analysis described in this article, events containing like-sign muon pairs are selected and their invariant mass distribution is compared to the SM prediction
The ATLAS Collaboration has previously reported an inclusive search for new physics in the like-sign dilepton final state in a data sample corresponding to an integrated luminosity of 34 pbÀ1 [22]
Summary
Events containing two high-pT, prompt, like-sign leptons are rarely produced in the standard model (SM), but occur with an enhanced rate in several models of new physics. In the analysis described in this article, events containing like-sign muon pairs are selected and their invariant mass distribution is compared to the SM prediction. The ATLAS Collaboration has previously reported an inclusive search for new physics in the like-sign dilepton final state in a data sample corresponding to an integrated luminosity of 34 pbÀ1 [22]. Like-sign top-quark pair production has previously been searched for by the CDF [25] and the CMS Collaborations [26]. The interpretation of the data as a cross-section upper limit within the fiducial region, for four ranges of dimuon invariant mass, and its implication on like-sign top-quark pair production are reported in Secs.
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