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Status Report of The CMS Experiment

Status Report of The CMS Experiment

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Status Report of The CMS Experiment

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  1. Status Report of The CMS Experiment Christos Leonidopoulos CERN-PH on behalf of the CMS Collaboration 102nd LHCC Meeting, CERN 7 July 2010

  2. The Collaboration • AACHEN-1, AACHEN-3A, AACHEN-3B, ADANA-CUKUROVA, ANKARA-METU, ANTWERPEN, ATHENS, ATOMKI, AUCKLAND, BARI, BEIJING-IHEP, BOGAZICI, BOLOGNA, BOSTON-UNIV, BRISTOL, BROWN-UNIV, BRUNEL, BRUSSEL-VUB, BRUXELLES-ULB, BUDAPEST, CALTECH, CANTERBURY, CARNEGIE-MELLON, CATANIA, CCCS-UWE, CERN, CHANDIGARH, CHEJU, ILLINOIS-CHICAGO, CHONNAM, CHUNGBUK, CHUNGLI-NCU, COLORADO, CORNELL, DEBRECEN-IEP, DELHI-UNIV, DEMOKRITOS, DESY, DONGSHIN, DUBLIN-UCD, DUBNA, EINDHOVEN, FAIRFIELD, FERMILAB, FIRENZE, FLORIDA-FIU, FLORIDA-STATE, FLORIDA-TECH, FLORIDA-UNIV, FRASCATI, GENOVA, GHENT, HAMBURG-UNIV, HEFEI-USTC, HELSINKI-HIP, HELSINKI-UNIV, HEPHY, IOANNINA, IOWA, IPM, ISLAMABAD-NCP, JOHNS-HOPKINS, KANGWON, KANSAS-STATE, KANSAS-UNIV, KARLSRUHE-IEKP, KHARKOV-ISC, KHARKOV-KIPT, KHARKOV-KSU, KONKUK-UNIV, KOREA-UNIV, KYUNGPOOK, LAPP, LAPPEENRANTA-LUT, LIP, LIVERMORE, LONDON-IC, LOUVAIN, LYON, MADRID-CIEMAT, MADRID-UNIV, MARYLAND, MEXICO-IBEROAM, MEXICO-IPN, MEXICO-PUEBLA, MEXICO-UASLP, MILANO-BICOCCA, MINNESOTA, MINSK-INP, MINSK-NCPHEP, MINSK-RIAPP, MINSK-UNIV, MISSISSIPPI, MIT, MONS, MOSCOW-INR, MOSCOW-ITEP, MOSCOW-LEBEDEV, MOSCOW-MSU, MOSCOW-RDIPE, MUMBAI-BARC, MYASISHCHEV, NAPOLI, NEBRASKA, NICOSIA-UNIV, NORTHEASTERN, NORTHWESTERN, NOTRE DAME, NUST, OHIO-STATE, OVIEDO, PADOVA, PAVIA, PEKING-UNIV, PERUGIA, PISA, POLYTECHNIQUE, PRINCETON, PROTVINO, PSI, PUERTO RICO, PURDUE, PURDUE-CALUMET, RAL, RICE, RIE, RIO-CBPF, RIO-UERJ, ROCHESTER, ROCKEFELLER, ROMA-1, RUTGERS, SACLAY, SANTANDER, SAO PAULO, SEONAM, SEOUL-EDU, SEOUL-SNU, SHANGHAI-IC, SKK-UNIV, SOFIA-CLMI, SOFIA-INRNE, SOFIA-UNIV, SPLIT-FESB, SPLIT-UNIV, ST-PETERSBURG, STRASBOURG, SUNY-BUFFALO, TAIPEI-NTU, TALLINN, TASHKENT, TBILISI-IHEPI, TBILISI-IPAS, TENNESSEE, TEXAS-TAMU, TEXAS-TECH, TIFR-EHEP, TIFR-HECR, TORINO, TRIESTE, UCDAVIS, UCLA, UC RIVERSIDE, UC SANTA BARBARA, UC SAN DIEGO, UNIANDES, VANDERBILT, VILNIUS-ACADEMY, VILNIUS-UNIV, VINCA, VIRGINIA-TECH, VIRGINIA-UNIV, WARSAW-IEP, WARSAW-INS, WARSAW-ISE, WAYNE, WISCONSIN, WONKWANG, YEREVAN, ZAGREB-RUDJER, ZURICH-ETH, ZURICH-UNIV • 182 Institutions • 3000 scientists and engineers • 2000 Authors

  3. Reminder: we went from this… 3.8T Superconducting Solenoid Hermetic (|η|<5.2) Hadron Calorimeter (HCAL) [scintillators & brass] Lead tungstate E/M Calorimeter (ECAL) All Silicon Tracker (Pixels and Microstrips) Redundant Muon System (RPCs, Drift Tubes, Cathode Strip Chambers)

  4. …to this First 7 TeV collisions in CMS – 30 March 2010

  5. …and this, just three months later

  6. Life did not begin in a vacuumwith the first collisions

  7. One Billion Cosmic Muons before collisions

  8. 23 JINST papers: March 2010 (Vol. 5) Feedback into realistic simulation to help us prepare for collisions

  9. Detector understanding • Claim: • Cosmic runs/beam tests have made a difference • First data distributions agree well with simulation • “Why should we believe that the simulation correctly describes the detector performance?” • Excellent question! • TeVatron experience: it takes a long time to commission & understand collider experiments • Accelerator, detector, trigger, background, underlying event, software: very complicated problems

  10. From data-taking to the plots • CMS is still in the commissioning phase • Hard work, long hours • Despite early phase and complexity of experiment • Unprecedented levels of readiness • Very encouraging first results • But: • Always problems seeking solutions • Hardest part is ahead of us

  11. Operations

  12. Integrated luminosity • Since end of March (7 TeV): • 100 nb-1 delivered (*) • 88 nb-1 recorded (~88%) L≈ 1030cm-2s-1 L≈ 1027-1029 cm-2s-1 (*) Stable beams only • ~3/4 of data recorded arrived in last 10 days • Working hard to integrate full datasets for ICHEP • Most performance plots use only fraction of data

  13. Subdetectors status Alignment/calibration status, dead/masked channels mirrored in MC

  14. “The Trigger does not determine which Physics Model is Right.Only which Physics Model is Left.”

  15. DAQ/Trigger • L1/DAQ rate: 45 kHz, @<0.5 MB/evt • High-Level Trigger: have successfully deployed online trigger menus spanning luminosities from 1E27 through 2E30 • Very smooth running throughout (200-400 Hz) • HLT CPU-performance: 49 ms/evt • Primary contributors: commissioning • and early analysis triggers • Contingency: factor of 2 • Constantly on watch list Run 138737 Overflows taken into account in the mean

  16. Trigger Performance • HLT muon efficiency wrt L1 • L1 objects matched to offline objects • ~90% efficiency at the plateau • Photon efficiency wrt offline • “super clusters” • For barrel & endcaps • Nearly 100% efficient

  17. Predicting trigger rates: MC vs. data “Building trigger menus 101”

  18. Predicting trigger rates: MC vs. data • Monte Carlo: • Only used as a cross-check at this point • Some trigger paths have significant cosmic or noise distributions that are not modeled with “baseline” MC • Still, impressive agreement overall • Using MC to cross-check 4.6E29 rates

  19. Predicting trigger rates: MC vs. data • Data: • Most triggers exhibit fairly linear behavior vs. luminosity • Extrapolation errors minimized by using most recent data to keep the rate non-linearities under control • Rates of all main players are predicted within ~20% • Using 1.2E29 rates to predict 4.6E29 rates

  20. Calibration Trigger Streams • Calibration triggers have access to full L1 rate, and they output small fraction of event • Feature unique to CMS HLT • Calibration starts online!

  21. Trigger calibration streams • Calibration triggers have access to full L1 rate, and they output small fraction of event • π0peak reconstructed offline 200 seconds into 7 TeV run 30 March 2010

  22. Trigger has accepted LHC has delivered CMS will analyze

  23. Analysis Activity 7 TeV data Routinely delivering 100k jobs per day October 09 MC Exercise Winter Break 10-20k analysis jobs running on Tier-2s continuously every day of June

  24. Physics production

  25. 3+1 CMS papers since May

  26. CMS paper at 7TeV “Transverse Momentum and Pseudorapidity Distributions of Charged Hadrons in pp Collisions at √s=7TeV”, submitted to PRL • Rise of the particle density at (2.36) 7 TeV steeper than in models • Careful tuning effort of the MC generators is ongoing

  27. Detector & Physics Performance Calorimetry JetsTracking b-taggingMuonEWK/Onia Particle Flow ElectronEWK/Onia

  28. Detector & Physics Performance Calorimetry JetsTracking b-taggingMuonEWK/Onia Particle Flow ElectronEWK/Onia

  29. Calorimetry: π0and η → γγ MC based correction applied according to cluster η and energy 1.46M of π0 → γγ PT(γ) > 0.4 GeV, PT(pair) > 1 GeV DATA MC 0.43 nb-1 1.46M π0 25.5K η → γγ PT(γ) > 0.5 GeV, PT(pair) > 2.5 GeV DATA MC 0.43 nb-1 25.5k η • Statistics refer to < 0.5 nb-1 • Very useful tool to intercalibrate the crystals • Good agreement in width and Signal/Background ratio • Masses agree with expectations to within 1%

  30. Calorimetry: Missing ET Calorimetric MET (GeV) • Jets reconstructed with the anti-kT R=0.5 algorithm • Dijet selection : Jet PΤ> 25 GeV, Δφ> 2.1, |η| < 3 • Loose ID cuts on number of components and neutral/charged energy fraction

  31. Detector & Physics Performance Calorimetry JetsTracking b-taggingMuonEWK/Onia Particle Flow ElectronEWK/Onia

  32. Calorimetric di-jet events Dijet mass Δφ(j1, j2) # of Calo Towers Fraction of EM energy in Calo-Jets

  33. Detector & Physics Performance CalorimetryJetsTracking b-taggingMuonEWK/Onia Particle Flow ElectronEWK/Onia

  34. Tracking distributions

  35. Muon distributions “Global Muons”: matched tracks from Muon system and Tracker Global Muons Global Muons • η and pT distributions dominated by light hadron decay muons (red) • good agreement with MC prediction, including • heavy flavor decays (blue) • punch-through (black) • fakes (green)

  36. Tracking distributions ηdistribution φdistribution pTspectrum

  37. Tracker Material Budget ηdistribution φdistribution

  38. Tracker Material Budget ηdistribution φdistribution pixel cluster charge

  39. Tomography

  40. Detector & Physics Performance CalorimetryJetsTrackingb-taggingMuonEWK/Onia Particle Flow ElectronEWK/Onia

  41. b-tagging 3D IP significance • 3D impact parameter value and significance • all tracks with pT> 1GeV belonging to jets with pT > 40 GeV and |η| < 1.5 - PFlowJets anti-kT R=0.5) Excellent alignment and general tracking performance

  42. b-tagging example Two b-jets candidate

  43. CMS experiment at LHC, CERN Run 136100 / Event 256858438 2010-25-5 03:43:48 CEDT B-→ J/yK- candidate

  44. CMS experiment at LHC, CERN Run 136100 / Event 256858438 2010-25-5 03:43:48 CEDT B-→ J/yK- candidate All other tracks: pT > 1.0 GeV/c

  45. Detector & Physics Performance CalorimetryJetsTrackingb-taggingMuonEWK/Onia Particle Flow ElectronEWK/Onia

  46. Particle Flow • Particle Flow: Full Event reconstruction • Topological matching between charged particle momenta measured with tracker with clusters in calorimeter • Corrects for energy loss along trajectories • Better precision, full event info • High-level object: requires holistic detector view • Excellent tracker • High E/M calorimeter granularity (0.017 × 0.017) • Strong magnetic field to separate tracks • CMS very well suited for P-Flow reconstruction

  47. Particle Flow MET

  48. Particle Flow MET Laser forgotten on Need cleaning strategies developed based on timing constraints

  49. Particle Flow MET Comparison between calorimetric and Particle-Flow MET (Minimum bias events)

  50. Detector & Physics Performance CalorimetryJetsTrackingb-taggingMuonEWK/OniaParticle Flow ElectronEWK/Onia