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Status and Plans of the CMS Experiment

Status and Plans of the CMS Experiment. Darin Acosta University of Florida On behalf of the CMS Collaboration. Dijet recorded 12/6/09, E T ~25 GeV. Outline. Start-up of the LHC State of the CMS experiment Recent results from the LHC start-up Prospects for early physics measurements.

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Status and Plans of the CMS Experiment

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  1. Status and Plans of the CMS Experiment Darin Acosta University of Florida On behalf of the CMS Collaboration Dijet recorded 12/6/09, ET~25 GeV

  2. Outline • Start-up of the LHC • State of the CMS experiment • Recent results from the LHC start-up • Prospects for early physics measurements D.Acosta - Miami 2009

  3. 2009/10 LHC Beam commissioning strategy Global machine checkout Essential 450 GeV commissioning Trial ramps Machine protection commissioning 1 Experiments’ magnets at 450 GeV Xmas 450 GeV collisions Ramp commissioning to 1.2 TeV System/beam commissioning Machine protection commissioning 2 3.5 TeV beam & first collisions 2010 Full machine protection qualification System/beam commissioning Pilot physics D.Acosta - Miami 2009

  4. The LHC Start-Up in 2009 • Injection Tests Oct.23-25 & Nov.7-9 • Nov.20, 18:00, Start of 2009 beam circulation • First beam 1 circulation by 20:40 • RF captured beam 1 for several minutes by 21:50, 4 hours after start! • Beam 2 captured by 0:10 • Nov.23, First collisions at 900 GeV • 13:30, both beams in, evidence for collisions at ATLAS (P1), LHCb, and ALICE • 19:00, Second attempt for CMS (P5), tuning,collisions seen! About 30min. • Dec.6, First physics fills • 5:00, collisions, 4 proton bunches/beam, ~4 hours • Dec.8, Acceleration • 21:44: both beams ramped to 1.18 TeV each • Dec.11, Higher proton intensities (7E10) • Starting to accumulate luminosity at 900 GeV • Dec.14, Collisions at 2.36 TeV ! • 4:00: about 2 hours of highest energy pp collisions • 21:00: still higher intensity 900 GeV collisions (16 bunches, 1.8E11) D.Acosta - Miami 2009

  5. Start of the LHC Physics Program ! • First collisions on Nov.23 at 900 GeV • ~0.1 Hz collisions • L ~ few 1024 cm-2s-1 • In the last week, collisions at 900 and 2236 GeV • ~10Hz collisions • L ~ few 1026 cm-2s-1 • Ultimately, the LHC program should take us to: • 14 TeV • 109 Hz collisions • L ~ 1034 cm-2s-1 = 1/L 23-Nov-09 14-Dec-09 Spring-2010  2011 D.Acosta - Miami 2009

  6. The Compact Muon Solenoid (CMS) (4T) 210 m2 of silicon sensors: 9.6M (Str) & 66M (Pix) channels 2 planes of silicon modules for ECAL Iron / Quartz fiber fwd calorimeter, 3<||<5; + Castor, 5<||<6.55 + Zero Degree Calorimeter Scintillator/brass Cathode Strip Chambers, Drift Tubes, Resistive Plates PbWO4 crystals (76K) + Trigger and data acquisition systems: 50 kHz into High Level Trigger (100 kHz max), record O(100) Hz D.Acosta - Miami 2009

  7. CMS Detector Subsystems Barrel pixels Crystal calorimeter, 1/2 of one endcap Silicon strip modules Barrel muon system (1/5 wheels) Magnet Hadron calorimeter (1/2 barrel) Endcap muon system (1/8 disks) D.Acosta - Miami 2009

  8. CMS in Closed Configuration D.Acosta - Miami 2009

  9. CMS Global Commissioning Program • During 2007 and 2008, commissioned progressively larger fractions of the systems for global data-taking • Integration of detector components and data acquisition system • Synchronization of detector signals with cosmic rays • Calibration and alignment with cosmic rays • Restarted in 2009 during last shutdown D.Acosta - Miami 2009

  10. First LHC Beams, 2008 HCAL energy ECAL energy • Beam onto collimators (splash events) • Halo muons from circulating beams  • But program cut shortdue to the major fault in one LHC sector particle debris D.Acosta - Miami 2009

  11. The Cosmic Runs At Four Tesla • CRAFT08: • 23 days from Oct.13 – Nov.11, 2008 • 270M cosmic triggers with B=3.8T Followed by shutdown, then: • CRAFT09: • 40 days from July 23 – Sept.1, 2009 • 320M cosmic triggers with B=3.8T • Commission the experimentwith magnet at operating field • Operate the experiment for an extended period (month) • Collect ~300M cosmics for detector studies D.Acosta - Miami 2009

  12. Detector Performance Publications • 23 CMS detector performance papers (500 pages!) submitted to the Journal of Instrumentation based on data from CRAFT08 and 2008 beams • Available on ArXiv: • http://arxiv.org/find/all/1/au:+CMS/0/1/0/all/0/1?skip=0&query_id=9f85c0e5eae277b4 • To appear in a single volume of JINST • Coverage: • Performance of all major detector systems, including trigger • Precision mapping of magnetic field in the steel return yoke • Performance of track and muon reconstruction algorithms • Alignment and calibration D.Acosta - Miami 2009

  13. CRAFT Results in Thumbnails D.Acosta - Miami 2009

  14. Alignment of the Silicon Strip and Pixel Trackers • Distributions of the means ofthe residuals, barrel components • Much improved from the survey accuracy of O(100m) • Close to ideal alignment even before collisions Barrel Pixel: 2.6 m Tracker inner barrel: 2.5 m Tracker outer barrel: 2.6 m D.Acosta - Miami 2009

  15. Tracking Performance • Efficiency and resolution measurements • Tag a muon in the muon detectors and study the inner tracker (or vice versa) • Split a cosmic track into 2 “legs” and compare them • Silicon tracking efficiency • 99.5% for muons passing completely through the detector and close to the beamline • Muon momentum resolution • 1% for pT=10 GeV, increasing to 8% for pT~500 GeV (should improve to 5% when detectors are perfectly aligned) D.Acosta - Miami 2009

  16. ’08-’09 Shutdown – CMS Activities • After the cosmics run (Nov ‘08), detector was opened for maintenance & repair activities, installation of preshower subdetector & CASTOR forward calorimeter. • Work progressed according to the schedule laid down in Nov. 2008. • Major Accomplishments: • Removal, repair, and re-insertion of the forward pixel system • Installation and commissioning of the preshower detector • Completion of maintenance & (some) repairs of all sub-systems • Completion of the revision of the tracker cooling plant • Understanding of magnetic field in the return iron-yoke • Overpressure protection (new item) • Re-commissioning of CMS • New TOSCA B Field Map – agreement of data & MC now better than 2% • Large Monte Carlo production & analysis exercise at 10 & 7 TeV D.Acosta - Miami 2009

  17. TID TEC Detector and Data-Taking Status for CRAFT09 Average CRAFT09 data-taking efficiency: 71% Without service disruptions: > 80% Operational Fractions Subdetector Strips: 98.1% Pixels: 98.5% Strip Tracker Status Map: 1 control ring 1 cooling loop D.Acosta - Miami 2009

  18. 2009 LHC Operations

  19. Beam “Splash” (~109protons onto upstream collimator) Nov.7-9, 2009 injectiontests Beam 2 RPC muon hits are in yellow, and CSC muon hits are in magenta. • ECAL energy deposits in red, HCAL energy deposits in blue (light blue for HF and HO) Silicon strips and pixels off for safety D.Acosta - Miami 2009

  20. ECAL vs. HCAL Observed Energy EndCap+ Barrel EndCap- O(1M) muons per event  1000’s of TeV/event! D.Acosta - Miami 2009 • O(1000) splash events in a wide range of beam intensity • Good linear correlation between ECAL and HCAL measured energies • Response in EndCap+ is lower than EndCap- due to particle losses from material in CMS

  21. Synchronization with Splash Events, HCAL Splash09 - Before Splash09: After HCAL Barrel: RMS= 1.9 ns HCAL Barrel: RMS= 1.2 ns Corrections checked with new splash events HCAL Endcap: RMS= 2.3 ns HCAL Endcap: RMS= 1.4 ns Similar timing improvements were achieved in ECAL Endcap and Preshower D.Acosta - Miami 2009

  22. ECAL Occupancy CMS 2009 Preliminary ECAL Endcap - ECAL Endcap + • Average energy per crystal in ECAL • White regions are masked channels • 0.9% of total • one quarter may be recovered. • Use coarse trigger data to recover allbut 0.15% • Energy modulations are combination of energy flow traversing CMS & geometry effects. • For the hadron calorimeter, no dead channels =1.5  = 3 ECAL Barrel ECAL Barrel =1.5 bottom =0 = -1.5 beam D.Acosta - Miami 2009

  23. Collisions ! • Dec.6, Early Sunday morning • First “physics” fill of the LHC with 450 GeV beams colliding for several hours (Very first collisions were provided Nov.23 with partial tracking) • All CMS detectors powered, including pixel and strip trackers, magnet on D.Acosta - Miami 2009

  24. Muons • Much lower rate than cosmic rays at this luminosity D.Acosta - Miami 2009

  25. Dimuon Candidate at 2.36 TeV D.Acosta - Miami 2009

  26. Rediscover mesons: 0 • Mass uncorrected for effects of the readout threshold of ECAL that had to be lowered, and material effects • Data will be used to intercalibrate the ECAL crystals, precision expected is O(1%) Data Simulation D.Acosta - Miami 2009

  27. Rediscover mesons:  • Mass and width compatible with MC • h yield scale as expected: • N(h) / N(p0) = 0.020 ± 0.003 DATA • N(h) / N(p0) = 0.021 ± 0.003 MC Data Simulation D.Acosta - Miami 2009

  28. Rediscover mesons and baryons: K0,  • K0s Ks  1.115 GeV 0.4975 GeV • Tracking reconstruction software working • These events tagged by separated vertex (V0) • Magnetic field calibrated (mapped to precision <0.1%) D.Acosta - Miami 2009

  29. K0s Candidate at 2.36 TeV D.Acosta - Miami 2009

  30. Rediscover the Standard Model: Jets CMS Experiment at the LHC, CERN Date Recorded: 2009-12-06 07:18 GMT Run/Event: 123596 / 6732761 Candidate Dijet Collision Event CMS Preliminary Anti-KT algorithm with cone size R=0.7 D.Acosta - Miami 2009

  31. Multi-jet Candidate at 2.36 TeV D.Acosta - Miami 2009

  32. (To come) Rediscover the Standard Model: QCD • Soft: Charged hadron measurements at 900 GeV up to 10 TeV • Pseudo-rapidity distribution expectedwith only 5K events  • Also underlying event properties 10 TeV • Hard: Inclusive jet cross section measurements  Example for 10pb-1 at 10 TeV with kT algoirthm D.Acosta - Miami 2009

  33. (To come) Rediscover the Standard Model: EWK • To be followed by measurements of, for example, the rapidity distribution and PT(Z) -- understanding of PDFs and pQCD at LHC 10 TeV 10pb-1 Two isolated electrons with ET>20 and ||<2.5 Systematic uncertainty: 2.4%  10% (lumi) Isolated muon with PT>25 and ||<2 D.Acosta - Miami 2009

  34. Discover! New Z’ gauge boson • Feasibility study • Luminosity required for 5 discovery as a function of Z’ mass in dimuon decay channel (very similar for dielectron) for two models and for several machine collision energies • Need  100 pb-1 at 10 TeV for discovery of mass > 1 TeV D.Acosta - Miami 2009

  35. p b b p ~ q Discover! SUSY Opposite sign dileptons • Dilepton edges in MSSM: • PTl>16; 3 jets ET>100, 50, 50; MET>100 • Feasibility study of LM0: • m0=200, m1/2=160, A0=-400, µ>0, tan=10 •  = 150 pb • 52.7 GeV endpoint • 200pb-1 of 10 TeV data, fit shape: • Mll,max = 51.31.5(stat) 0.9(syst) Opposite sign, e +  Opposite sign, ee,  D.Acosta - Miami 2009

  36. Future Plans • LHC stopped 2009 operations yesterday, Dec-16 • A short shutdown follows for XMAS and to complete commissioning of the LHC quench protection system in January • CMS will use the short shutdown for maintenance • Replacement of cooling circuit connections on endcaps • We resume operations in Feb-2010 with operations at a 3.5 TeV beam energy • Deemed safe with remaining anomalous resistance in some splices between magnets • Possible step-up to 4 to 5 TeV beam energy after ~3 months, requiring one month to reestablish physics, and running another 4-5 months • Heavy ion collider run for 1 month at end D.Acosta - Miami 2009

  37. Conclusions • After a long road of design, construction, and commissioning the CMS experiment and the LHC are here! • All detector systems are operational • Excellent synchronization, alignment and calibration precision achieved using cosmic rays and initial beam data • Achieved high operational data-taking efficiency • Recorded data from cosmic muons, “beam splashes”, and collisions at 900 and 2360 GeV (& many known resonances seen!) CMS is ready for physics ! D.Acosta - Miami 2009

  38. Backup

  39. The Large Hadron Collider (LHC) • 27 km ring • 7 TeV maximum beam energy • 3.5 TeV for startof 2010 • 0.45 TeV @ injection • 1232 superconducting 8.4T dipole magnets @ T=1.9ºK • 4 experiments • ATLAS, CMS • ALICE, LHCb • First launched Sept.10, 2008 D.Acosta - Miami 2009

  40. CRAFT09 Data Acquisition All systems in, including Preshower detector > 4700 applications running on 672 PCs for High Level Trigger Efficient running with 80 kHz input rate Huge muon trigger rate, DAQ still ok D.Acosta - Miami 2009

  41. radiative collision Muon dE/dX Measured in Calorimeters • HCAL: Measurement of the energy loss in the barrel hadron calorimeter as a function of measured muon momentum, compared to Monte Carlo • ECAL: Measurement of the absolute energy loss in PbWO4 as a function of measured muon momentum, compared to calculation D.Acosta - Miami 2009

  42. Silicon Strip Tracker: Signal / Noise APV Pulse shape Peak mode Signal to noise ratio Deconvolution mode Change of cosmic trigger type Signal/Noise CMS preliminary Deconvolution mode is the APV readout mode planned for LHC operation (narrow pulse shaping to minimize pile-up from out-of-time collisions)  Implemented for second half of CRAFT09 The ratio S/N (Peak/Deconvolution) is ~ 1.7 as expected (x1.5 noise and x0.9 signal) and sufficiently high for efficient hit identification D.Acosta - Miami 2009 42

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