895 research outputs found
Searches for rare or BSM top quark decays at the LHC
No full textRecently approved results for rare or beyond Standard Model processes involving top quark decays from ATLAS and CMS observed in collision data from the LHC running with TeV are described. From ATLAS, there are exclusion limits for light charged Higgs bosons decaying to a hadronic lepton and neutrino and to . Exclusion limits for flavor-changing neutral current processes and are also presented. From CMS, exclusion limits for a charged Higgs boson decaying to a lepton and for flavor-changing neutral currents in the process are presented. No evidence for processes beyond the Standard Model are observed
Data-driven Background Estimations in H+ Analyses
No full textA description of data-driven methods used in H+ analyses. These methods include embedding for true tau backgrounds, and matrix methods for fake tau and lepton backgrounds
The Demand for Automated Bibliographic Systems: A Diffusion Model
No full textThe rapid increase in scientific literature has necessitated finding more efficient ways to locate the studies of relevance. For example, the number of biomedical journals increased from five in 1799 to more than twenty-three thousand in 1977 (McCarn, forthcoming). For the biomedical literature, the first large-scale attempt to search bibliographic references using a computer was the MEDLARS system of the National Library of Medicine (see McCarn and Leiter, 1973 for a description). As originally set up, the system was designed for batch processing; the user communicated by mail, and a search request typically took several weeks to process.</p
Study of Tau Leptons from Top Quark Pairs in ATLAS
No full textTop quark pair decay events resulting in final states containing τ leptons present interesting channels in the search for physics beyond the Standard Model. This document describes the in-progress analyses of two channels, τ+jets and τ+l in ttbar decays, for the case of a hadronically decaying τ lepton. The studied events are from 1.03 fb−1 of proton-proton collision data at √s = 7 TeV recorded by the ATLAS Collaboration at the LHC
[Photograph 2012.201.B0420.0200]
No full textPhotograph used for a story in the Oklahoma Times newspaper. Caption: "Brothers Donald and Dennis McCarn both received their Eagle rank from Troop 34 sponsored Mayfair Elementary School.
Search for vector-like quarks with the ATLAS Detector
No full textVector-like quarks appear in many theories beyond the Standard Model as a way to cancel the mass divergence for the Higgs boson. The current status of the ATLAS searches for the production of vector-like quarks is reviewed for proton-proton collisions with = 13 TeV produced by the Large Hadron Collider. The results and the complementarity of the various searches are discussed
Search for a charged Higgs Boson in proton-proton collisions at the LHC using the ATLAS detector
No full textThis thesis documents several searches for charged Higgs bosons () in the decay , which are performed using data recorded in 2011 and 2012 by the ATLAS detector at the LHC. The bosons are predicted by some extensions of the Standard Model (SM) that include multiple Higgs doublet fields, such as the Minimal Supersymmetric Standard Model. None of these searches has found evidence for the existence of , and exclusion limits are set on and .
For the 2011 ATLAS dataset, searches are performed for light \Hpm, defined by \mH < m_{top}, on a data sample corresponding to an integrated luminosity of 4.6 \invfb proton-proton collisions with = 7 TeV. These searches are conducted using the decay channel \ttbar \rightarrow Wb \Hpm b, with \Hpm \rightarrow \tau_{had} \nu and the boson decaying hadronically (+jets channel) or leptonically (+lepton). The combination of the channels in this search excludes at 95 confidence level (CL) a branching fraction of B(t \rightarrow \Hp b) \times B(\Hp \rightarrow \tau \nu) = 1-5 \% for the mass range \mH = 90-160 GeV.
An additional search, with the aim of observing \Hpm through apparent violation of lepton universality in a ratio of yields, is also performed on this dataset. In this search, the \ttbar \rightarrow \ell \nu b \tau \nu b event yield is compared to that of \ttbar \rightarrow \ell \nu b \ell' \nu b. The signal would contribute to these yields through \Hpm replacing the boson in the SM \ttbar decay and preferentially decaying to . Combining this search with the +jets channel results in an improved 95 CL exclusion on the branching fraction of B(t \rightarrow \Hp b) \times B(\Hp \rightarrow \tau \nu) = 0.8-3.4 \% for the mass range \mH = 90-160 GeV.
For the 2012 ATLAS dataset, searches for an extended mass range of \Hpm are performed on a data sample corresponding to an integrated luminosity of 19.5 \invfb proton-proton collisions at = 8~TeV. These \Hpm searches are for final states involving a hadronic and jets, both in \ttbar decays and top-associated production. For \Hpm with \mH m_{top}, 95 CL limits are set on \sigma_{H^+} \times B(\Hp \rightarrow \tau \nu) of pb, for a mass range of \mH = 180-600 GeV.Item withdrawn by Mark Zulauf ([email protected]) on 2013-06-05T18:48:22Z
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University of Illinois Theses & Dissertations (ID: 1)
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A dissertation on infancy
No full textearly student thesis: 'A Dissertation on Infancy', Sarah J. McCar
[A Child Standing near a Car with a Trailor]
No full textPhotograph of Small girl standing next to a 1928 Erskine automobile and traile
Extended Scalar Searches at 13 TeV in ATLAS and CMS
No full textThese proceedings document the content of the presentation at the 2016 Moriond Electroweak Conference covering searches for extended scalars in ATLAS and CMS Collaborations. The presentation placed an emphasis on new results using proton--proton collisions provided at = 13 TeV by the Large Hadron Collider and recorded by the ATLAS and CMS detectors. The recorded data includes an integrated luminosity of 3.2 fb and up to 2.8 fb for the ATLAS and CMS detectors, respectively. The new results include searches for a charged Higgs boson, as well as for a neutral heavy Higgs decaying to leptons, additional neutral Higgs bosons, two Higgs bosons of =~125~GeV, Standard Model bosons, and invisible final states
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