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

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

17 December 2009 D.Acosta - Miami /10 LHC Beam commissioning strategy Global machine checkout Essential 450 GeV commissioning System/beam commissioning Machine protection commissioning TeV beam & first collisions 450 GeV collisions Ramp commissioning to 1.2 TeV Full machine protection qualification Pilot physics System/beam commissioning Machine protection commissioning 1 EnergySafeVery Safe 4501 e121 e11 1 TeV2.5 e112.5 e TeV3.0 e10probe Experiments’ magnets at 450 GeV Trial ramps Xmas 2010

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

17 December 2009 D.Acosta - Miami Start of the LHC Physics Program ! 23-Nov-09 Spring-2010 n First collisions on Nov.23 at 900 GeV u ~0.1 Hz collisions u L ~ few cm -2 s -1 n In the last week, collisions at 900 and 2236 GeV u ~10Hz collisions u L ~ few cm -2 s -1 n Ultimately, the LHC program should take us to: u 14 TeV u 10 9 Hz collisions u L ~ cm -2 s Dec-09 = 1/L  2011

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

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

17 December 2009 D.Acosta - Miami CMS in Closed Configuration

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

17 December 2009 D.Acosta - Miami First LHC Beams, 2008 HCAL energy ECAL energy particle debris  n Beam onto collimators (splash events) n Halo muons from circulating beams  u But program cut short due to the major fault in one LHC sector

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

17 December 2009 D.Acosta - Miami Detector Performance Publications n 23 CMS detector performance papers (500 pages!) submitted to the Journal of Instrumentation based on data from CRAFT08 and 2008 beams u Available on ArXiv: l u To appear in a single volume of JINST n Coverage: u Performance of all major detector systems, including trigger u Precision mapping of magnetic field in the steel return yoke u Performance of track and muon reconstruction algorithms u Alignment and calibration

17 December 2009 D.Acosta - Miami CRAFT Results in Thumbnails

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

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

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

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

2009 LHC Operations

17 December 2009 D.Acosta - Miami Beam “Splash” (~10 9 protons onto upstream collimator ) Beam 2 Nov.7-9, 2009 injection tests n ECAL energy deposits in red, HCAL energy deposits in blue (light blue for HF and HO) RPC muon hits are in yellow, and CSC muon hits are in magenta. Silicon strips and pixels off for safety

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

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

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

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

17 December 2009 D.Acosta - Miami Muons u Much lower rate than cosmic rays at this luminosity

17 December 2009 D.Acosta - Miami Dimuon Candidate at 2.36 TeV

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

17 December 2009 D.Acosta - Miami Rediscover mesons:  Data Simulation n Mass and width compatible with MC  yield scale as expected:  N(  ) / N(  0 ) = ± DATA  N(  ) / N(  0 ) = ± MC

17 December 2009 D.Acosta - Miami Rediscover mesons and baryons: K 0,  n K0s KsKs  GeV GeV n Tracking reconstruction software working u These events tagged by separated vertex (V0) n Magnetic field calibrated (mapped to precision <0.1%)

17 December 2009 D.Acosta - Miami K 0 s Candidate at 2.36 TeV

17 December 2009 D.Acosta - Miami Rediscover the Standard Model: Jets CMS Experiment at the LHC, CERN Date Recorded: :18 GMT Run/Event: / Candidate Dijet Collision Event Anti-K T algorithm with cone size R=0.7 Jet 1Jet 2 Corrected p T (GeV)2426   CMS Preliminary

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

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

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

17 December 2009 D.Acosta - Miami Discover! New Z’ gauge boson n Feasibility study u 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 u Need  100 pb -1 at 10 TeV for discovery of mass > 1 TeV

17 December 2009 D.Acosta - Miami Discover! SUSY Opposite sign dileptons u Dilepton edges in MSSM: u P T l >16; 3 jets E T >100, 50, 50; MET>100 u Feasibility study of LM0: l m 0 =200, m 1/2 =160, A 0 =-400, µ>0, tan  =10 l  = 150 pb l 52.7 GeV endpoint u 200pb -1 of 10 TeV data, fit shape: l M ll,max = 51.3  1.5(stat)  0.9(syst) Opposite sign, ee,  Opposite sign, e +  p p b b q ~

17 December 2009 D.Acosta - Miami Future Plans n LHC stopped 2009 operations yesterday, Dec-16 n A short shutdown follows for XMAS and to complete commissioning of the LHC quench protection system in January n CMS will use the short shutdown for maintenance u Replacement of cooling circuit connections on endcaps n We resume operations in Feb-2010 with operations at a 3.5 TeV beam energy u Deemed safe with remaining anomalous resistance in some splices between magnets n 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 n Heavy ion collider run for 1 month at end

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

Backup

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

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

17 December 2009 D.Acosta - Miami Muon dE/dX Measured in Calorimeters u ECAL: Measurement of the absolute energy loss in PbWO 4 as a function of measured muon momentum, compared to calculation collision radiative u HCAL: Measurement of the energy loss in the barrel hadron calorimeter as a function of measured muon momentum, compared to Monte Carlo

17 December 2009 D.Acosta - Miami Silicon Strip Tracker: Signal / Noise 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 APV Pulse shape Peak mode Deconvolution mode Change of cosmic trigger type Signal to noise ratio CMS preliminary Signal/Noise