ATLAS Status Report Part II Fabiola Gianotti RRB
ATLAS Status Report (Part II) Fabiola Gianotti, RRB, 11/10/2010 CERN-RRB-2010 -083 For detector, shut-down and upgrade activities see talk by M. Nessi High-mass di-jet event : Mjj = 3. 1 Te. V �Collaboration and Management matters �Highlights from data-taking and experiment operation �Physics and performance results (few examples) F. Gianotti, ATLAS RRB, 11/10/2010 p. T (j 1)=520 Ge. V p. T (j 2)=460 Ge. V 1
Collaboration and Management matters F. Gianotti, ATLAS RRB, 11/10/2010 2
3030 active scientists: -- ~ 1830 with a Ph. D contribute to M&O share -- ~ 1200 students 174 Institutions, 38 Countries Albany, Alberta, NIKHEF Amsterdam, Ankara, LAPP Annecy, Argonne NL, Arizona, UT Arlington, Athens, NTU Athens, Baku, IFAE Barcelona, Belgrade, Bergen, Berkeley LBL and UC, HU Berlin, Bern, Birmingham, UAN Bogota, Bologna, Bonn, Boston, Brandeis, Brasil Cluster, Bratislava/SAS Kosice, Brookhaven NL, Buenos Aires, Bucharest, Cambridge, Carleton, CERN, Chinese Cluster, Chicago, Chile, Clermont-Ferrand, Columbia, NBI Copenhagen, Cosenza, AGH UST Cracow, IFJ PAN Cracow, SMU Dallas, UT Dallas, DESY, Dortmund, TU Dresden, JINR Dubna, Duke, Edinburgh, Frascati, Freiburg, Geneva, Genoa, Giessen, Glasgow, Göttingen, LPSC Grenoble, Technion Haifa, Hampton, Harvard, Heidelberg, Hiroshima IT, Indiana, Innsbruck, Iowa SU, Iowa, UC Irvine, Istanbul Bogazici, Johannesburg/Witwatersrand, KEK, Kobe, Kyoto UE, Lancaster, UN La Plata, Lecce, Lisbon LIP, Liverpool, Ljubljana, QMW London, RHBNC London, UC London, Lund, UA Madrid, Mainz, Manchester, CPPM Marseille, Massachusetts, MIT, Melbourne, Michigan SU, Milano, Minsk NAS, Minsk NCPHEP, Montreal, Mc. Gill Montreal, RUPHE Morocco, FIAN Moscow, ITEP Moscow, MEPh. I Moscow, MSU Moscow, Munich LMU, MPI Munich, Nagasaki IAS, Nagoya, Naples, New Mexico, New York, Nijmegen, Northern Illinois University, BINP Novosibirsk, NPI Petersburg, Ohio SU, Okayama, Oklahoma, Oklahoma SU, Olomouc, Oregon, LAL Orsay, Osaka, Oslo, Oxford, Paris VI and VII, Pavia, Pennsylvania, Pisa, Pittsburgh, CAS Prague, CU Prague, TU Prague, IHEP Protvino, Regina, Rome II, Rome III, Rutherford Appleton Laboratory, DAPNIA Saclay, Santa Cruz UC, Sheffield, Shinshu, Siegen, Simon Fraser Burnaby, SLAC, Stockholm, KTH Stockholm, Stony Brook, Sydney, Sussex, AS Taipei, Tbilisi, Tel Aviv, Thessaloniki, Tokyo ICEPP, Tokyo MU, Tokyo Tech, Toronto, TRIUMF, Tsukuba, Tufts, Udine/ICTP, Uppsala, UI Urbana, Valencia, UBC Vancouver, Victoria, Waseda, Washington, Weizmann Rehovot, FH Wiener Neustadt, Wisconsin, Wuppertal, Würzburg, Yale, Yerevan F. Gianotti, ATLAS RRB, 11/10/2010 3
3030 active scientists: -- ~ 1830 with a Ph. D contribute to M&O share -- ~ 1200 students 174 Institutions, 38 Countries F. Gianotti, ATLAS RRB, 11/10/2010 4
Collaboration composition since the last RRB At its Collaboration Board (CB) meeting on 2 July 2010, the Collaboration unanimously admitted a new joint team (a “cluster” 1 vote in the CB): University of Johannesburg and University of the Witwatersrand, South Africa DST/NRF is a new Funding Agency in ATLAS q An Expression of Interest had been presented at the February 2010 CB and announced to the April 2010 RRB q The South Africa team consists today of about 10 scientists. Several positions have been open recently (or will be open in the near future) to strengthen the team. Members of the team have been active in ATLAS for some time through affiliation to other Institutions (e. g. BNL, Oxford). q The South Africa team is involved in several activities, with full satisfaction of the Project Leaders and Activity Coordinators, including: Muon performance and software validation, SCT operation, Tracker Upgrade They are contributing successfully to high-priority tasks for the experiment. They are also working to establish Tier-3 s and later a Tier-2 q Half of the cash member fees (137 k. CHF) has been paid, the other half included in the recently approved DST budget for SA-CERN cooperation F. Gianotti, ATLAS RRB, 11/10/2010 5
Collaboration composition since the last RRB At its Collaboration Board (CB) meeting on 2 July 2010, the Collaboration unanimously admitted a new joint team (a “cluster” 1 vote in the CB): University of Johannesburg and University of the Witwatersrand, South Africa DST/NRF is a new Funding Agency in ATLAS q An Expression of Interest had been presented at the February 2010 CB and announced to the April 2010 RRB q The South Africa team consists today of about 10 scientists. Several positions have been open recently (or will be open in the near future) to strengthen the team. Members of is thekindly team have been active in ATLAS for some timeof through affiliation The RRB requested to endorse the admission this new to team other in Institutions (e. g. BNL, Oxford). the ATLAS Collaboration q The South Africa team is involved in several activities, with full satisfaction of The total number of Institutions (with voting rights in the CB) the Project Leaders and Activity Coordinators, including: increases from and 173 software to 174, and the number of FA from 42 Upgrade to 43 Muon performance validation, SCT operation, Tracker They are contributing successfully to high-priority tasks for the experiment. They are also working to establish Tier-3 s and later a Tier-2 q Half of the cash member fees (137 k. CHF) has been paid, the other half included in the recently approved DST budget for SA-CERN cooperation F. Gianotti, ATLAS RRB, 11/10/2010 6
ATLAS Management extended for a second mandate (1 March 201128 February 2013) F. Gianotti, ATLAS RRB, 11/10/2010 7
Martine Bosman (IFAE Barcelona) has been elected new (Deputy) CB Chair, with term: q January 1 st - 31 st December 2011: Deputy Chair q January 1 st 2012 -31 st December 2013: Chair q January 1 st - 31 st December 2014: Deputy Chair The Collaboration (and ATLAS Management in particular) is very grateful to Kerstin Jon-And (Stockholm) for her excellent work as (Deputy) CB Chair over the last four years F. Gianotti, ATLAS RRB, 11/10/2010 8
Highlights from data-taking and experiment operation F. Gianotti, ATLAS RRB, 11/10/2010 9
Integrated luminosity vs time (from first √s =7 Te. V collisions on 30 March until this morning) > 3 Te. V mass di-jet event 1 st W 1 st top-quark candidate 1 st Z Peak luminosity in ATLAS: ~8. 8 x 1031 cm-2 s-1 Recorded/delivered luminosity: ~ 91% (some losses due to machine backgrounds) Total recorded by ATLAS: 14. 4 pb-1 : q ~ 3. 5 pb-1 until end of August q. F. Gianotti, ~ 11 pb-1 ATLAS since. RRB, 22 September (machine operating with bunch trains) 11/10/2010 10
Total fraction of good quality data (green “traffic light”) Few percent losses in EM calorimeter due to sporadic noise bursts and HV trips (conservative, being improved) Trigger rates at each level vs time during a fill 3 levels: L 1 (hardware), L 2, Event Filter (EF) q Very good performance (operational, efficiency, …) q Coping very well with rapidly-increasing luminosity by adapting prescales, thresholds and menu F. Gianotti, ATLAS RRB, 11/10/2010 Trigger output (recorded rate): ~ 300 Hz Luminosity in this fill: 3. 2 2. 8 x 1031 11
Computing infrastructure and operation ATLAS w. LCG world-wide computing: ~ 70 sites (including CERN Tier-0, 10 Tier-1 s, ~ 40 Tier-2 federations) WLCG F. Gianotti, ATLAS RRB, 11/10/2010 12
Worldwide data distribution and analysis Total throughput of ATLAS data through the Grid: 1 st January yesterday MB/s per day Jan 6 GB/s Feb March Start of 7 Te. V data-taking 2009 data reprocessing April May June July Data and MC reprocessing 1011 p/bunch operation Aug Sep multi-bunch operation O c t bunch trains ~2 GB/s (design) Peaks of 10 GB/s achieved Grid-based analysis in Summer 2010: > 1000 different users; > 15 M analysis jobs The excellent Grid performance has been crucial for fast release of physics results. E. g. : ICHEP: the. RRB, full 11/10/2010 data sample taken until Monday was shown at the conference on Friday 13 F. Gianotti, ATLAS
Physics and performance results (few examples …) F. Gianotti, ATLAS RRB, 11/10/2010 14
Di-muon resonances Very simple analysis: q trigger: LVL 1_MU 6 q 2 opposite-sign muons reconstructed by combining tracker and muon spectrometer q both muons with |z|<1 cm from primary vertex J/ψ is one of the first “candles” for detector commissioning and early physics (B-physics, QCD). Provides large samples of low-p. T muons to study μ trigger and identification efficiency, resolution and absolute momentum scale. RRB, in the few Ge. V range F. Gianotti, ATLAS 11/10/2010 15
Di-muon resonances J/ψ mass resolution vs muon η Inner Detector J/ψ mass peak vs muon η 5 Me. V From J/ψ mass peak and resolution reconstructed in the Inner Detector: absolute momentum scale known to ~ 0. 2% and momentum resolution to ~2 % in the few Ge. V region F. Gianotti, ATLAS RRB, 11/10/2010 PDG Inner Detector 16
Jet physics Data sample: ~ 3 pb-1 Leading jet p. T > 160 Ge. V, other jets p. T > 30 Ge. V Shape comparisons between data and parton-shower MC (distributions normalized to unity) F. Gianotti, ATLAS RRB, 11/10/2010 17
Observed event with hardest jet in first ~ 3 pb-1 p. T (jet) > 1. 1 Te. V p. T (j 1)= 1120 Ge. V p. T (j 2)= 480 Ge. V p. T (j 3)= 155 Ge. V p. T (j 4)= 95 Ge. V F. Gianotti, ATLAS RRB, 11/10/2010 Event display shows uncalibrated energies 18
Inclusive jet cross-section q Measured jets corrected to particle-level using partonshower MC (Pythia, Herwig): justified by detailed comparison studies and good agreement with data p. Tj > 60 Ge. V, |yj|< 2. 8 Submitted for publication in EPJC NLOJET++ q Results compared to NLO QCD prediction after corrections for hadronization and underlying event q Theoretical uncertainty: ~20% (up to 40% at large |yj|) from variation of PDF, αs, scale (μR, μF) q Experimental uncertainty: ~30 -40% dominated by Jet E-scale (known to ~7%, thanks to detailed data/MC comparison foundation work, see previous examples) Luminosity (11%) not included Good agreement data-NLO QCD over 5 orders of magnitude F. Gianotti, ATLAS RRB, 11/10/2010 19
W and Z physics q Fundamental milestones in the “rediscovery” of the Standard Model at √s = 7 Te. V q Among dominant backgrounds to searches for New Physics q Powerful tools to constrain q, g distributions inside proton (PDF) q Z ll is gold-plated process to calibrate the detector to ultimate precision (E and p scales and resolutions in EM calo, tracker, muon spectrometer; lepton identification, …) F. Gianotti, ATLAS RRB, 11/10/2010 20
Data sample: ~ 3 pb-1 μ e After requiring a good lepton p. T > 20 Ge. V W eν: 9929 evts After all cuts Observed in data: W μν : 10397 events W eν: 9929 events W μν: 10397 evts F. Gianotti, ATLAS RRB, 11/10/2010 MC normalised to data 21
W cross-section and asymmetry measurements Submitted for publication in JHEP σ (W lν) = 9. 96 ± 0. 23 (stat) ± 0. 5 (syst) ± 1. 1 (lumi) nb ATLAS: A = 0. 20 ± 0. 02 (stat) ± 0. 01 (syst) F. Gianotti, ATLAS RRB, 11/10/2010 22
Z cross-section and W/Z cross-section ratio Submitted for publication in JHEP σ ( γ*/Z ll) = 0. 82 ± 0. 06 (stat) ± 0. 05 (syst) ± 0. 09 (lumi) nb R (theory) = 10. 840 ± 0. 054 Measured Z peaks: Z μμ 90. 9 ± 0. 1 Ge. V (MC: 91. 3 Ge. V) Z ee 90. 8 ± 0. 1 Ge. V (MC: 91. 6 Ge. V) Z ee experimental mass resolution: 1. 59 ± 0. 04 Ge. V (MC: 1. 40 ± 0. 01 Ge. V) F. Gianotti, ATLAS RRB, 11/10/2010 23
W τν, Z ττ Reconstructed μ and τ F. Gianotti, ATLAS have opposite sign RRB, 11/10/2010 Signals more difficult to observe due to softer (visible) lepton spectrum and larger backgrounds 24
Top-quark candidates lepton + jets channel tt b. W blν bjj σ ~ 70 pb 1 isolated lepton p. T > 20 Ge. V ETmiss > 20 Ge. V, ETmiss + m. T > 60 Ge. V ≥ 4 jets p. T > 25 Ge. V ≥ 1 b-tag jet Acceptance x efficiency ~ 15% 2 -lepton channel tt b. W blν σ ~ 10 pb 2 opposite-sign leptons: ee, eμ, μμ both leptons p. T > 20 Ge. V ≥ 2 jets p. T > 20 Ge. V ee: ETmiss > 40 Ge. V |M(ee)-MZ|> 5 Ge. V μμ: ETmiss > 30 Ge. V |M(μμ)-MZ|> 10 Ge. V eμ: HT = ΣET (leptons, jets) > 150 Ge. V Acceptance x efficiency ~ 25% Expect ~ 30 signal events for ~ 3 pb-1 Expect ~ 7 signal events for ~ 3 pb-1 e, μ ν F. Gianotti, ATLAS RRB, 11/10/2010 25
A gold-plated tt beν bμν candidate p. T(μ)= 51 Ge. V p. T(e)=66 Ge. V p. T (b-tagged jets) = 174, 45 Ge. V ETmiss = 113 Ge. V, Secondary vertices: -- distance from primary vertex: 4 mm, 3. 9 mm -- vertex mass : ~2 Ge. V, ~ 4 Ge. V F. Gianotti, ATLAS RRB, 11/10/2010 Purity > 96% 26
A gold-plated tt beν bμν candidate p. T(μ)= 51 Ge. V p. T(e)=66 Ge. V p. T (b-tagged jets) = 174, 45 Ge. V ETmiss = 113 Ge. V, Secondary vertices: -- distance from primary vertex: 4 mm, 3. 9 mm -- vertex mass : ~2 Ge. V, ~ 4 Ge. V Purity > 96% The era of top-quark physics at the LHC has started F. Gianotti, ATLAS RRB, 11/10/2010 27
First searches for New Physics Present goals: q understand backgrounds by comparing MC to data for key search-sensitive distributions ( complementary studies to Standard Model analyses) q start to set competitive limits with Tevatron two results shown here q be prepared for discoveries when enough data available Typically: q few pb-1: start to compete with Tevatron sensitivity q O (100 pb-1 ): discovery (5σ) potential (just) beyond Tevatron limits q ~ 1 fb-1: discovery potential extends into new territory, e. g. Backgrounds to gluino R-hadrons -- W’ up to m~ 2 Te. V decaying in the calorimeters -- SUSY up to m (squarks, gluinos) ~ 750 Ge. V out-of-time of collisions F. Gianotti, ATLAS RRB, 11/10/2010 28
Searches for excited quarks: q* jj Look for di-jet resonance in the measured M(jj) distribution Previous best published limit: CDF (1 fb-1): 260 < M (q*) < 870 Ge. V spectrum compatible with a smooth monotonic function no bumps q August 2010: with 315 nb-1 : 0. 4 < M (q*) < 1. 26 Te. V excluded at 95% C. L. beyond the Tevatron for the first time published: PRL 105, 161801 (2010) q Today: with 3. 1 pb-1 analyzed: limit extended to ~ 1. 5 Te. V 1. 53 Te. V q p. T (j 1, j 2) > 150, 30 Ge. V, |η|<2. 5, |η 1 -η 2|<1. 3, mjj> 350 Ge. V q Experimental systematic uncertainties (luminosity, jet E-scale, background fit, …) included F. Gianotti, RRB, 11/10/2010 q Impact. ATLAS of theoretical uncertainties (PDF, scale): < 100 Ge. V 29
Searches for quark contact interactions Look for deviations from QCD in dijet angular distributions ϑ* = polar angle of the dijet system q QCD: χ distribution ~ flat (t-channel g-exchange dominates) q Contact interactions (characterized by a scale Λ) or new massive physics: excess at low χ for large M(jj) q p. T (j 1, j 2) > 60, 30 Ge. V, |y 1+y 2|<1. 5, M(jj) >340 Ge. V q Jet E-scale and PDF uncertainties included Λ > 3. 4 Te. V at 95% C. L. Latest published limit: D 0 (0. 7 fb-1): 2. 84 Te. V Submitted for publication in Phys Lett B (ar. Xiv: 1009. 5069) F. Gianotti, ATLAS RRB, 11/10/2010 30
Conclusions F. Gianotti, ATLAS RRB, 11/10/2010 31
Since 30 March, ATLAS has recorded > 14 pb-1 at √s =7 Te. V We are very grateful to the LHC team for their effort to bring the machine to such excellent performance ! q The whole experiment has worked efficiently and fast, from data taking at the pit (with efficiency > 90%), through data processing and transfer worldwide, to prompt delivery of performance and physics results. q The performance of the detector and the quality of the reconstruction and simulation software much better than expected at this (initial) stage of the experiment (and close to nominal in some cases …). q The Grid is a success, and has been crucial to enable the worldwide Collaboration to participate in the data analysis quickly and effectively ATLAS has started to exploit in earnest the LHC physics potential, in particular: q measurements of the jets, W, Z cross-sections submitted for publication q observation of the top quark q searches for New Physics first limits exceeding the Tevatron published or submitted q~ 100 results/notes submitted to Summer Conferences q 3 papers published, 3 more submitted for publication Results will become more and more rich and exciting in the months to come In parallel: detector consolidation and Upgrade activities progress with vigor, e. g. : q First Upgrade TDR (IBL) approved by the Collaboration submitted to the LHCC q R&D work, projects (e. g. FTK) and plans for Phase 1 and Phase 2 q Organizational and management structure of the Upgrade projects being finalized q First ideas about Mo. U and funding model being discussed with CERN Management and F. Gianotti, RRB, Physicists 11/10/2010 National. ATLAS Contact 32
ATLAS is very grateful to the Funding Agencies for their huge contributions to the success of the experiment and their continuous support during almost 20 years. F. Gianotti, ATLAS RRB, 11/10/2010 33
Spares F. Gianotti, ATLAS RRB, 11/10/2010 34
Age distribution of the ATLAS population All 2690 Male 81. 8% Female 18. 2% (Status 1. 1. 2010) (< 35 y 47. 2%) 44. 0%) 61. 3%) More than 1000 Ph. D students F. Gianotti, ATLAS RRB, 11/10/2010 35
Muon Spectrometer (| |<2. 7) : air-core toroids with gas-based muon chambers Muon trigger and measurement with momentum resolution < 10% up to E ~ 1 Te. V 3 -level trigger reducing the rate from 40 MHz to ~200 Hz Length : ~ 46 m Radius : ~ 12 m Weight : ~ 7000 tons ~108 electronic channels 3000 km of cables Inner Detector (| |<2. 5, B=2 T): Si Pixels, Si strips, Transition Radiation detector (straws) Precise tracking and vertexing, e/ separation Momentum resolution: /p. T ~ 3. 8 x 10 -4 p. T (Ge. V) 0. 015 EM calorimeter: Pb-LAr Accordion e/ trigger, identification and measurement HAD calorimetry (| |<5): segmentation, hermeticity E-resolution: /E ~ 10%/ E Fe/scintillator Tiles (central), Cu/W-LAr (fwd) Trigger and measurement of jets and missing ET E-resolution: /E ~ 50%/ E 0. 03 F. Gianotti, ATLAS RRB, 11/10/2010 36
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