1300177 SzGeCERN 20121219160002.0 ATL-COM-PHYS-2010-854 eng CERN-ATL-COM-PHYS-2010-854 Collaboration, ATLAS Observation of top quark pair production in ATLAS at sqrt{s}=7 TeV 2010 Geneva CERN 14 Oct 2010 27 p The observation of ttbar production in pp collisions at a centre-of-mass energy sqrt(s) = 7 TeV is presented. In a data sample of 2.9 pb−1 recorded by the ATLAS detector at the Large Hadron Collider, 37 candidate events are observed in the single lepton topology with electrons or muons, and 9 in the dilepton topology. The corresponding backgrounds from non-ttbar Standard Model processes are estimated largely from data control samples. When all channels are combined, the background-only hypothesis is excluded at a significance level of 4.9 standard deviations. Kinematic properties of the selected events are consistent with Standard Model ttbar production. The ttbar production cross-section is measured to be sigma(ttbar) = 146 +37-33 +49-30 pb, where the first uncertainty is statistical, the second is systematic. CERN CDS-Invenio WebSubmit SzGeCERN Detectors and Experimental Techniques SzGeCERN Physics CERN Top CERN Cross-section CERN TOP CERN INTNOTE PRIVATLAS CERN LHC ATLAS PH-EP http://cds.cern.ch/record/1300177/files/ATL-COM-PHYS-2010-854.pdf sjolin@physto.se verkerke@nikhef.nl cristinz@uni-bonn.de Marina.Cobal@cern.ch bosman@ifae.es pamelaf@nikhef.nl loginov@fnal.gov n 201070 90 20101014 2232 CER01 20101014 PUBLIC 000710682CER INTNOTEATLASPRIV 1300178 SzGeCERN 20121219160002.0 ATL-COM-PHYS-2010-855 eng CERN-ATL-COM-PHYS-2010-855 Working group, Top Observation of top quark pair production in the semileptonic decay channel at sqrt(s) = 7 TeV with the ATLAS detector 2010 Geneva CERN 14 Oct 2010 36 p 'Supporting document for top paper' The first cross section measurements of ttbar production in pp collisions at a centre-of-mass energy sqrt(s) = 7 TeV are presented. In a data sample of 2.9 pb−1 recorded by the ATLAS detector at the Large Hadron Collider, 37 candidate events are observed in the semileptonic topology with electrons or muons. The corresponding backgrounds from non-ttbar Standard Model processes are estimated largely from data control samples, including the most important one: W+jets. Three different analyses have been developed to measure the ttbar production cross section: a simple counting method and two dfferent fitting techniques. The background-only hypothesis is excluded at a significance level of 4.2 standard deviations. Kinematic properties of the selected events are consistent with Standard Model ttbar production. INT CERN CDS-Invenio WebSubmit SzGeCERN Detectors and Experimental Techniques SzGeCERN Physics CERN TOP CERN INTNOTE PRIVATLAS CERN LHC ATLAS PH-EP http://cds.cern.ch/record/1316984 Approved Note http://cds.cern.ch/record/1300178/files/ATL-COM-PHYS-2010-855.pdf Access to fulltext document sjolin@physto.se verkerke@nikhef.nl cristinz@uni-bonn.de bosman@ifae.es Marina.Cobal@cern.ch loginov@fnal.gov pamelaf@nikhef.nl 21 Dec 2010 Approved as a Note n 201070 90 20101221 1742 CER01 20101014 PUBLIC 000710683CER INTNOTEATLASPRIV 1300179 SzGeCERN 20121219160002.0 ATL-COM-PHYS-2010-856 eng CERN-ATL-COM-PHYS-2010-856 Working group, Top Analysis of ttbar production in the dilepton decay channel at 7 TeV with 2.9 pb−1 2010 Geneva CERN 14 Oct 2010 30 p We present a first measurement of ttbar production with the ATLAS detector at the LHC in pp collisions at sqrt(s) = 7 TeV in final states with two oppositely-charged leptons (ee, mm and em), significant missing transverse energy (ETmiss) and two or more jets. In a dataset with integrated luminosity of 2.9 pb−1 we observe nine events in the dilepton channel. Using data-driven background techniques, we find good agreement in nearby control regions. The significance of the measurement, excluding the ttbar production, is estimated to be equivalent to 2.8 standard deviations. The kinematic properties of the excess events are consistent with the ttbar hypothesis. Interpreting this excess as ttbar production, we measure a cross section of sigma(ttbar) = 151 +85−68(stat) +39−26(syst) pb. INT CERN CDS-Invenio WebSubmit SzGeCERN Detectors and Experimental Techniques SzGeCERN Physics CERN TOP CERN INTNOTE PRIVATLAS CERN LHC ATLAS PH-EP http://cds.cern.ch/record/1317592 Approved Note http://cds.cern.ch/record/1300179/files/ATL-COM-PHYS-2010-856.pdf Access to fulltext document sjolin@physto.se verkerke@nikhef.nl cristinz@uni-bonn.de loginov@fnal.gov 23 Dec 2010 Approved as a Note n 201070 90 20101223 1144 CER01 20101014 PUBLIC 000710684CER INTNOTEATLASPRIV 1298247 SzGeCERN 20121219155703.0 ATL-COM-PHYS-2010-826 eng CERN-ATL-COM-PHYS-2010-826 Benekos, N University of Illinois Urbana-Champaign Lepton Trigger and Identification for the first {\it Top quark} observation 2010 Geneva CERN 07 Oct 2010 48 p Supporting document for top paper' (full list is here https://twiki.cern.ch/twiki/bin/view/AtlasProtected/FirstTopPaper) In this note we present the selections applied to identify leptons (electrons and muons) for the first Top WG \ttbar~cross section measurements in the single and di-lepton channels. We measure the associated efficiencies at the trigger and offline level using the {\it Tag and probe} method, on the same dataset using for the cross section measurement, corresponding to an integrated luminosity of $\mathscr{L} = 2.89~\ipb$. We describe the procedure to rescale the MC-based acceptance used for the cross section measurements to represent data accurately; and we provide the value and uncertainties on the Scale Factors at all selection stages. The scale and the resolution difference in the determination of the lepton momentum, with respect to MC expectations, is also provided. INT CERN CDS-Invenio WebSubmit SzGeCERN Detectors and Experimental Techniques SzGeCERN Physics CERN Cross section CERN Lepton Identification CERN Efficiencies CERN Resolution CERN TOP CERN INTNOTE PRIVATLAS CERN LHC ATLAS Benslama, K University of Regina Bosman, M IFAE Cerrito, L Queen Mary University of London Derue, F LPNHE Ferrara, V Humboldt-Universitaet zu Berlin Ferrari, P Nikhef Fiorini, L IFAE Heelan, L University of Carleton Heim, S Michigan State University Helsens, C IFAE Henrichs, A Georg-August-Universitaet Goettingen Husegawa, S Nagoya University Ju, X University of Regina Juste, A IFAE Kaplan, B Yale Krasznahorkay, A New York University Kumar Jana, D University of Oklahoma Lessard, J University of Victoria Loginov, A Yale Ming, Y University of Regina Mir, L IFAE Nadal, J IFAE Okumura, Y Nagoya University Papadelis, A Stockholm University Poll, J Queen Mary University of London Ryan, P Michigan State University Roe, A Georg-August-Universitaet Goettingen Salamanna, G Nikhef Schwienhorst, R Michigan State University Shabalina, E Georg-August-Universitaet Goettingen Sherman, D Yale Sidoti, A Humboldt-Universitaet zu Berlin Theveneaux-Pelzer, T LPNHE Tipton, P Yale Vorwerk, V IFAE Zhu, H DESY PH-EP http://cds.cern.ch/record/1312944 Approved Note http://cds.cern.ch/record/1298247/files/ATL-COM-PHYS-2010-826.pdf Access to fulltext document giuseppe.salamanna@cern.ch Lucio.Cerrito@cern.ch 08 Dec 2010 Approved as a Note n 201070 90 20101208 1849 CER01 20101007 PUBLIC 000710379CER INTNOTEATLASPRIV 1298782 SzGeCERN 20121219155729.0 ATL-COM-PHYS-2010-835 eng CERN-ATL-COM-PHYS-2010-835 Arguin, J F Lawrence Berkeley National Lab. Jet selection for top physics 2010 Geneva CERN 08 Oct 2010 61 p Supporting document for top paper (see https://twiki.cern.ch/twiki/bin/view/AtlasProtected/FirstTopPaper) This note summarizes the current status of the definition of jets for the top-rediscovery effort. Studies on the data quality, jet cleaning and calibration are shown before more analysis-related topics are discussed. These include studies on the jet energy scale, resolution and efficiency. The note ends with a preliminary proposal for the jet definition which is done in accordance with the Jet/ETmiss-group. INT CERN CDS-Invenio WebSubmit SzGeCERN Detectors and Experimental Techniques SzGeCERN Physics CERN jets CERN jet quality CERN jet cleaning cuts CERN jet calibration CERN jet reconstruction efficiency CERN jet resolution CERN jet inter-calibration CERN gamma-jet CERN b-jet scale CERN out-of-cone CERN close-by jets CERN quark-gluon content CERN jets in top CERN TOP CERN INTNOTE PRIVATLAS CERN LHC ATLAS Boumediene, D LPC, Clermont Ferrand Bondioli, M University of California, Irvine Cortiana, G Max-Planck-Institut fuer Physik, Muenchen Costa Mezquita, M Instituto de Fisica Corpuscular (IFIC), Centro Mixto UVEG-CSIC Cowden, C University of Cambridge DeViveiros, P-O University of Toronto Doglioni, C University of Oxford Erdmann, J University of Goettingen Ferrando, J University of Oxford Gaponenko, A Lawrence Berkeley National Lab. Ghodbane, N LPC, Clermont Ferrand Issever, C University of Oxford Liao, H LPC, Clermont Ferrand Kovesarki, P University of Bonn Kroeninger, K University of Goettingen Lemmer, B University of Goettingen Lessard, J-R University of Victoria Losada, M Antonio Narino University, Bogota Marti I Garcia, S Instituto de Fisica Corpuscular (IFIC), Centro Mixto UVEG-CSIC Loureiro Mattioli, K Antonio Narino University, Bogota Moreno Llacer, M Instituto de Fisica Corpuscular (IFIC), Centro Mixto UVEG-CSIC Nisius, R Max-Planck-Institut fuer Physik, Muenchen Okawa, H University of California, Irvine Petteni, M Simon Fraser University Piegaia, R University of Buenos Aires Psoroulas, S University of Bonn Romeo, G University of Buenos Aires Ruehr, F University of Arizona Spanò, F Columbia University Urbaniec, D Columbia University Lopez Mateos, D Columbia University, California Institute of Technology Adomeit, S Ludwig-Maximilians-University of Munich Biebel, O Ludwig-Maximilians-University of Munich Pleier, M-A Brookhaven National Lab. Kroseberg, J University of Bonn Hellmich, D University of Bonn Yang, U University of Manchester Martyniuk, A University of Manchester Pallin, D LPC, Clermont Ferrand PH-EP http://cds.cern.ch/record/1312952 Approved Note http://cds.cern.ch/record/1298782/files/ATL-COM-PHYS-2010-835.pdf Access to fulltext document francesco.spano@cern.ch kevin.alexander.kroeninger@cern.ch 08 Dec 2010 Approved as a Note n 201070 90 20101208 2300 CER01 20101008 PUBLIC 000710502CER INTNOTEATLASPRIV 1297971 SzGeCERN 20121219155654.0 ATL-COM-PHYS-2010-821 eng CERN-ATL-COM-PHYS-2010-821 Canepa, A TRIUMF Missing Transverse Energy for Top Physics analyses with early ATLAS data at $sqrt{s}$=7~TeV 2010 Geneva CERN 06 Oct 2010 42 p Supporting document for top paper This note describes the object based missing transverse energy reconstruction and performance used in Top Physics analyses performed with 2.89ipb{} of data recorded by the ATLAS detector at ts{}=7~TeV. INT CERN CDS-Invenio WebSubmit SzGeCERN Detectors and Experimental Techniques SzGeCERN Physics CERN Top CERN ttbar CERN Missing transverse energy CERN Etmiss CERN JETetmiss CERN TOP CERN INTNOTE PRIVATLAS CERN LHC ATLAS Cinca, D University Blaise Pascal Clermont-Ferrand II Farrell, S University of California Irvine Garitaonandia Elejabarrieta, H Nikef Grundler, U Iowa State University Johns, K University of Arizona Kaushik, V University of Arizona Khandanya, H University of Illinois Urbana Champaign Lei, X University of Arizona Lessard, JR University of Victoria Liss, T University of Illinois Urbana Champaign Nugent, I TRIUMF Okawa, H University of California Irvine Pallin, D University Blaise Pascal Clermont-Ferrand II Taffard, A University of California Irvine Toggerson, B University of California Irvine Watson, M University of Birmingham PH-EP http://cds.cern.ch/record/1312953 Approved Note http://cds.cern.ch/record/1297971/files/note3_v3.pdf anyes.taffard@cern.ch 08 Dec 2010 Approved as a Note n 201070 90 20101208 2300 CER01 20101006 PUBLIC 000710333CER INTNOTEATLASPRIV 1299555 SzGeCERN 20121219155816.0 ATL-COM-PHYS-2010-846 eng CERN-ATL-COM-PHYS-2010-846 Alvarez, B B-tagging for top physics analyses with early ATLAS data at sqrt(s) = 7 TeV 2010 Geneva CERN 12 Oct 2010 38 p Supporting document for top paper Algorithms distinguishing jets originating from $b$ quarks from other jet flavors are important tools in top physics to improve purity and combinatorical background. This document describes the algorithms to identify $b$-quark jets in ATLAS and the calibration techniques based on LHC collider data. The performance of these algorithms is discussed for tbar{} cross section measurements at a centre of mass energy of 7~TeV{} for an integrated luminosity of about 3~ipb{}. INT CERN CDS-Invenio WebSubmit SzGeCERN Detectors and Experimental Techniques SzGeCERN Physics CERN TOP CERN BTAGGING CERN INTNOTE PRIVATLAS CERN LHC ATLAS Bachacou, H Boudreau, J Bousson, N Cerrito, L Clement, B Cooper, B Delemontex, T Donini, J Feligioni, L Filthaut, F Garberson, F Golling, T Guindon, S Guo, B Helsens, C Hirsch, F Holzbauer, J Juste, A Kendziorra, C Khanov, A Kroninger, K Liu, C Lapoire, C Lucotte, A zur Nedden, M Oakham, G Pinamonti, M Pope, B Rizatdinova, F Saleem, M Schwienhorst, R Schwindling, J Shabalina, E Sinervo, P Skubic, P Suruliz, K Talby, M Tannoury, N Vacavant, L Walsh, B Wang, J Yu, J PH-EP http://cds.cern.ch/record/1312946 Approved Note http://cds.cern.ch/record/1299555/files/ATL-COM-PHYS-2010-846.pdf Access to fulltext document tobias.golling@yale.edu 08 Dec 2010 Approved as a Note n 201070 90 20101208 1859 CER01 20101012 PUBLIC 000710622CER INTNOTEATLASPRIV 1299575 SzGeCERN 20121219155916.0 ATL-COM-PHYS-2010-849 eng CERN-ATL-COM-PHYS-2010-849 Abi, B Mis-identified lepton backgrounds to top quark pair production Supporting note 5 2010 Geneva CERN 13 Oct 2010 62 p Supporting note for top observation paper The note presents an analysis of the mis-identified lepton (``fake'') backgrounds to top quark pair production in the single-lepton and dilepton channels. Several data driven methods are used in each channel to estimate these backgrounds and assess the corresponding systematic uncertainties. This draft describes the various methods and their performance in simulated events; we present an estimate of the fake lepton contribution to the top-mix sample, as well as the estimates of the fake background in the 2.9 pb-1 dataset. INT CERN CDS-Invenio WebSubmit SzGeCERN Detectors and Experimental Techniques SzGeCERN Physics CERN Fake lepton background CERN dilepton channel CERN single lepton channel CERN top quark pair production CERN TOP CERN INTNOTE PRIVATLAS CERN LHC ATLAS Adelman, J Almond, J Arguin, J F Besana, I Bordoni, S Bosman, M Brau, J Cortes-Gonzalez, A Doxiadis, A Feligioni, L Fiorini, L Gellerstedt, K Golling, T Helsens, C Hickman, M Hirschbuehl, D Husemann, U Juste, A Khanov, A Khoriauli, G Lange, C Lari, T Liss, T Meloni, F Mir, L Nadal, J Owen, M Radics, B Rajagopalan, S Ridel, M Rizatdinova, F Saleem, M Searcy, M Shabalina, E Sjolin, J Sturm, P Talby, M Tannoury, N Tardif, D Tipton, P Trincaz-Duvoid, S Troncon, C van~Vulpen, I Vorwerk, V Wall, R Wagner, W Whiteson, D Yang, U K Zhou, N PH-EP http://cds.cern.ch/record/1317014 Approved Note http://cds.cern.ch/record/1299575/files/ATL-COM-PHYS-2010-849.pdf Access to fulltext document elizaveta.shabalina@cern.ch daniel@uci.edu verkerke@nikhef.nl cristinz@uni-bonn.de loginov@fnal.gov Marina.Cobal@cern.ch 22 Dec 2010 Approved as a Note n 201070 90 20101222 1043 CER01 20101013 PUBLIC 000710648CER INTNOTEATLASPRIV 1298781 SzGeCERN 20121219155728.0 ATL-COM-PHYS-2010-834 eng CERN-ATL-COM-PHYS-2010-834 Acharya, B Estimation of the W+Jets Background for Top Quark Re-Discovery in the Single Lepton+Jets Channel 2010 Geneva CERN 08 Oct 2010 30 p Supporting document for top paper W boson production in association with jets is predicted to be the dominant background to $t ar{t}$ events in the single lepton + jets channel. This note discusses the W+jets background to top pair production for two different luminosity scenarios. Firstly we discuss the issues relevant for the top observation for $int mathcal{L} dt$ = 2.9 pb$^{-1}$. We first describe a data-driven estimate of the W+jets background before b-tagging using the Berends-Giele scaling. The final estimate of the W+jets background after b-tagging is extracted by combining this pretag W+jets estimate with the W+jets tagged fraction obtained in the top group b-tagging note. The predicted number of W+$ge$4jet after b-tagging is 1.7$pm$1.1 and 2.9$pm$1.6 in the electron and muon channels, respectively. This section also contains detailed studies of the systematic uncertainties associated with the W+jets shape prediction, which is relevant to top cross-section analyses using a kinematic fit. Secondly we discuss the prospects for future data-driven methods which are applicable for datasets of 10 pb$^{-1}$ or more. In particular we discuss how to use the W charge asymmetry and W-to-Z ratios to extract the W+jets background in top analyses. INT CERN CDS-Invenio WebSubmit SzGeCERN Detectors and Experimental Techniques SzGeCERN Physics CERN top pair CERN W+jets CERN data-driven background estimate CERN TOP CERN INTNOTE PRIVATLAS CERN LHC ATLAS Arguin, J-F Barisonzi, M Besana, IM Bosman, M Brock, IC Calkins, R Charkaborty, D Cobal, M Cristinziani, M Ferrando, J Fiorini, L Henrichs, A Heinemann, B Helsens, C Khoriauli, G Kuhl, T Juste, A Lari, T Meloni, F Mir, L Nadal, J Nuncio-Quiroz, E Pinamonti, M Radics, B de Sanctis, U Shabalina, E Shan, L-Y Suruliz, K Ta, DB Troncon, C Vorwerk, V PH-EP http://cds.cern.ch/record/1312980 Approved Note http://cds.cern.ch/record/1298781/files/ATL-COM-PHYS-2010-834.pdf Access to fulltext document jfarguin@lbl.gov bacharya@ictp.it 09 Dec 2010 Approved as a Note n 201070 90 20101209 1551 CER01 20101008 PUBLIC 000710501CER INTNOTEATLASPRIV 1299083 SzGeCERN 20121219155748.0 ATL-COM-PHYS-2010-845 eng CERN-ATL-COM-PHYS-2010-845 Cranmer, K Study of Z/g+jets background for ttbar to 2 leptons analysis 2010 Geneva CERN 11 Oct 2010 19 p This note is a support note dedicated to Z/g+jets production as a background to the ttbar cross-section measurement in the dilepton channel. The output from the note is a baseline set of cuts for Z/g+jets rejection and an estimated yield, with uncertainty, of Z/g+jets events in the ttbar signal region. The estimate has been improved with respect to pure Monte Carlo using data driven techniques, and we present results for 2.9/pb of lepton-triggered ATLAS data. INT CERN CDS-Invenio WebSubmit SzGeCERN Detectors and Experimental Techniques SzGeCERN Physics CERN Drell-Yan CERN Top background CERN TOP CERN INTNOTE PRIVATLAS CERN LHC ATLAS Cristinziani, M Khandanyan, H Lewis, G Liss, T Papadelis, A Poghosyan, T Sherman, D Sjoelin, J Werth, M Whiteson, D PH-EP http://cds.cern.ch/record/1317593 Approved Note http://cds.cern.ch/record/1299083/files/ATL-COM-PHYS-2010-845.pdf Access to fulltext document sjolin@physto.se 23 Dec 2010 Approved as a Note n 201070 90 20101223 1144 CER01 20101011 PUBLIC 000710576CER INTNOTEATLASPRIV 1297704 SzGeCERN 20121219155651.0 ATL-COM-PHYS-2010-820 eng CERN-ATL-COM-PHYS-2010-820 Adelman, J Technical aspects of the first top pair analyses Note 8 2010 Geneva CERN 05 Oct 2010 21 p Support document for top paper This note is dedicated to the technical aspects of the first ATLAS top pair analyses. It describes derived physics data samples, the software used to produce and analyze the samples, steps taken to ensure the correctness of the software and reproducibility of the results. The overall data quality requirements and closely related calculation of the integrated luminosity are also presented here. INT CERN CDS-Invenio WebSubmit SzGeCERN Detectors and Experimental Techniques SzGeCERN Physics CERN top CERN ttbar CERN TopInputs CERN ntuple CERN dAOD CERN D2PD CERN TopPhys CERN data quality CERN luminosity CERN validation CERN TOP CERN INTNOTE PRIVATLAS CERN LHC ATLAS Barisonzi, M Bell, W H Brooijmans, G Cortiana, G Farrel, S Federic, P Ferrari, A Finelli, K Gaponenko, A Husemann, U Kumar Jana, D Lessard, J-R Lleres, A Lucotte, A Okawa, H Pleier, M-A Radics, B Searcy, J Taffard, A Urbaniec, D PH-EP http://cds.cern.ch/record/1317309 Approved Note http://cds.cern.ch/record/1297704/files/ATL-COM-PHYS-2010-820.pdf Access to fulltext document andrei.gaponenko@cern.ch lleres@lpsc.in2p3.fr 22 Dec 2010 Approved as a Note n 201070 90 20101222 1343 CER01 20101006 PUBLIC 000710326CER INTNOTEATLASPRIV 1298803 SzGeCERN 20121219155731.0 ATL-COM-PHYS-2010-836 eng CERN-ATL-COM-PHYS-2010-836 Allwood-Spires, S Monte Carlo samples used for top physics Top Working Group Note IX 2010 Geneva CERN 09 Oct 2010 38 p Supporting document for top paper This note documents the standard Monte Carlo samples to be used for top rediscovery analyses with 7 TeV data. The dataset numbers, cross sections and statistics are detailed. In addition the justification of k-factors for the different signal and background processes is discussed. A new tool for matching heavy flavour production events in Alpgen samples is described. INT CERN CDS-Invenio WebSubmit SzGeCERN Detectors and Experimental Techniques SzGeCERN Physics CERN TOP CERN INTNOTE PRIVATLAS CERN LHC ATLAS Barisonzi, M Beauchemin, H Bruneliere, R Buchanan, J Castro, N F Devetak, E Feng, C Ferrando, J Hawkings, R Hirschbuehl, D Husemann, U Kersevan, B P Khoriauli, G Kuhl, T Lenz, T Mijovc, L Papadelis, A Sanders, M P Shan, L-Y Sturm, P Veloso, F Verkerke, W Vlasov, N Wasicki, C PH-EP http://cds.cern.ch/record/1312945 Approved Note http://cds.cern.ch/record/1298803/files/ATL-COM-PHYS-2010-836.pdf Access to fulltext document j.ferrando1@physics.ox.ac.uk james.ferrando@cern.ch dhirsch@mail.cern.ch 08 Dec 2010 Approved as a Note n 201070 90 20101208 1859 CER01 20101009 PUBLIC 000710514CER INTNOTEATLASPRIV