Roberta Arcidiacono Universita' & INFN Torino on behalf of the CMS collaboration DIS09 – April 2009 Status of CMS

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 2 Overview  CMS detector and its commissioning  First LHC beam  CMS performance with cosmics  Shutdown activities  Plans and conclusions

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 3 Overview  CMS is built around a huge magnet: the largest superconducting magnet ever built  Solenoid, 13 m long, 6 m diameter, strong field (4T), 1.6 GJ of stored energy

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 4 CMS Detector ECAL Tracker HCAL Muon (DT+RPC) Muon (CSC+RPC) EM Calorimeter: Barrel & Endcap PbWO4 crystal calorimeter Hadronic calorimeter: Brass & scintillator Barrel, Endcap, Forward, Outer Tracker 66M Si pixels & 10M Si strips Muon chambers: Barrel: Drift Tubes - Endcap: Cathode Strip Chambers – Both interleaved with Resistive Plate Chambers Length: 21.6 m Diameter: 15 m Weight:12500 tons General purpose LHC collider

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 5 CMS particle ID layers

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 6 CMS Detector in Pictures 1 Nov06 HF- 9 Feb07 YB0 15 Jan08 YE-1 Insertion of Silicon Strip Tracker: Dec 08. Lowering detector in the cavern May 2006 – cavern empty, CMS on surface

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 7 Detector participation progress chart CMS Commissioning Underground ● Magnet Test and Cosmic Challenge (MTCC) in summer 2006 (surface) ● Commissioning started May 2007 – few to 10 days “global run”/month  Integrate CMS detector into DAQ  Test the trigger (L1, HLT) systems (cosmics/high rate randoms)  Exercise data transfer to Tier 0,1,2, reconstruction, alignment and calibration work-flows  Study read out synchronization and detector performance Activities interleaved with installation schedule and local commissioning plans ALL CMS with exception of ½ RPCE 100%

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 8 Cosmic Events Collected 290M events B=3.8 T (194M with all components in) 350M events B=0 T CRUZETs (Cosmics RUn at Zero Tesla) Detector open – magnet OFF CMS ready for BEAM: Detector closed - magnet OFF CRaFT - commissioning of solenoid in cavern (Cosmics Run at Four Tesla) 4 weeks long run with cosmic rays trigger, 19 days of B=3.8T Aiming to collect ~300M cosmic evts with tracker and DT chambers read out May 08 Fall 08 Sept 08

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 9 Cosmic Muon Event ECAL in magenta, HCAL in blue, tracker and Muon Hits in green

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 10 Final Closure – 3 Sept 2008

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 11 First LHC Beam Synchronization tests (September 5-9) Beam 1 (clockwise) “shots” onto a collimator 150 meters upstream of CMS → SPLASH EVENTS Circulating beams (September 10) 10:30 Beam 1 around the ring, up to ~3 turns 15:00 Beam 2 around the ring, up to 3-4 turns 22:00 Beam 2 circulates for hundreds of turns Beam protons interacting with Beam Elements and Beam Gas → BEAM HALO EVENTS RF capture of beam (September 11) → CMS: → CMS: ~40 hours of beam. All systems on, except for Tracker and Magnet Fri, Sept. 19 th A faulty electrical connection between a dipole and a quadrupole failed, massive helium loss, and cryogenics and vacuum lost → reparations and consolidation of safety systems ongoing

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 12 Splash Events Beam 1 at injection energy (450 GeV) stopped by upstream collimators closed Hundreds of thousands of muons pass through CMS per event. Enormous amount of energy deposited in calorimeters (170 TeV in ECAL, 1000 TeV in HCAL). Perfect tool to study occupancy, synchronization and bad channels CMS 146 m Collimato rs BPTX

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 13 Splash Events: Event Display Beam shots:~2x10 9 protons on collimator ~150 m from detector  ……………..  ………..  ……………. 13 ECAL Energy Drift Tubes HCAL Energy Shots direction LHC tunnel profile visible Beam triggers (BPTX, BSC) correctly timed in to CSC and HF trig.

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 14 Splash Events in ECAL Energy map for ECAL Endcaps and Barrel. The Endcaps are uncalibrated (lowest gain photodetectors are nearest the beam pipe) Detector time aligned within 1 ns.

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 15 Splash Events in HCAL Time difference between predicted pulse arrival time and mean pulse arrival time, before and after using delays tuned from beam splash events.  Note that HCAL Barrel region was already tuned with prior data.  HCAL now timed in at ns scale

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 16 Circulating Beam Orbit signals Multiple orbits detected by the CMS beam monitoring system BPTX: beam pickup, used for timing purposes, signals actual arrival of CMS traversed by BEAM HALO events. 89 µs BPTX After one turn From injection line Muons outside of beam-pipe, arising from decays of pions created when off-axis protons scrape collimators or other beamline elements. Interaction of beam protons with beam gas.

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 17 Beam Halo Events ME  4ME  3ME  2ME  1 LHC tunnel profile CSC hits distribution YE- Negative Yoke Endcap CSC Beam Halo event detected by CSC (3 muons)

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 18 Beam Halo: CSC Alignment Alignment done using tracks passing through two overlapping chambers Relative position determined by requiring consistency between track segments (and within a ring) Accuracy achieved: 270 μm in rφ plane 0.35 mrad in φ z Initial alignment goal reached in 9 min of LHC beam!

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 19  After the LHC accident, CMS has taken 300,000,000 cosmic ray muons at nominal magnetic field  These data have been a great source which allowed us to enhance detector and software quality  Large amount of data at 0 and 3.8 T collected:  Complete the commissioning of the reconstruction chain  Understanding of many aspects of CMS apparatus to a level which was estimated reachable only after pb -1 of LHC collisions  Efficiencies, alignments and magnetic field effects addressed  Analysed events span 5 orders of magnitude in muon multiplicity Performances with Cosmics TRACKS... SEGMENTS … HITS TRACKS... SEGMENTS … HITS COSMIC CHARGE RATIO SHOWER ORIGIN SHOWER ENERGY & SHAPE

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 20 Magnetic Field Map Magnet successfully tested on the surface in 2006 and then in the cavern FIELD MAP: 3 regions with different level of precision: Tracker, Tracker to Muon Chambers, Muon Chambers. Measured in 2006 on surface. Field calculated using TOSCA in the entire detector volume performed (at 2, 3, 3.5, 3.8, 4 T). → CRaFT (Fall 08) : First opportunity to measure Magnetic Field in the return yoke (where is difficult to model and measure) using muon tracks. Inside solenoid: - TOSCA model agrees with measurements done in 2006 < 0.1% - NMR probes confirmed agreement with 2008 measurements Outside solenoid: to achieve the same level of agreement we need better description of the field boundary conditions – ongoing

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 21 DT Muon Chambers (Barrel)  Efficiency is 100% in almost all Superlayers – few (temporary) disconnected channels +2+2 MB1 MB4 MB3 MB DT spatial resolution in de-bunched events (cosmics): Residuals (x Track – x RecHit ) RMS ~ 200–260 μm [expected ~200 μm for LHC beam muons]  TOF-compensated cosmic trigger: di-muon- like signal in DT

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 22 DT: B field effects Drift velocity in the Drift Tubes: key parameter for the muon trigger and reconstruction Innermost chambers in outermost wheels affected by B-field with a deviation up to 3%

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 23 HCAL Response to cosmic rays CRaFT data Energy deposit in HB for cosmic muons: Muon track matching in DT and Tracker 20 GeV/c < P µ < 1000 GeV/c CRAFT: 200 K events MC: 15 K events Energy corrected for muon path length in HB. Good agreement with MC and test beam results  Cosmic trigger from coincidence of m.i.p. signals in top and bottom part of HB (synchronized to muon triggers) HCAL+ECAL TestBeam

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 24 ECAL  e/γ trigger tested by triggering on m.i.p. signal  synchronized to muon & HCAL triggers 3x3 matrix energy deposit confirms absolute energy scale to few % Response to cosmic rays CRaFT data ● data total stopping power in PbWO4 collision loss bremsstrahlung Muons stopping power in ECAL Barrel Momentum measured in the tracker is the cluster energy (matching the track), corrected for the muon path length in the crystals. Only events in EB bottom are selected. → Correctness of the tracker momentum scale and of ECAL energy scale test beam) ECAL TestBeam

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 25 Si Strips Tracker Track hit finding efficiency TIB and TOB layers S/N S/N ratio for clusters associated to tracks, corrected for the track angle TOB thick sensors: S/N = 32 TIB/TID thin sensors: S/N = 27/25 TEC (mixed thickness): S/N = 30 Momentum distribution for high quality tracks: 8 hits, 1 hit in TIB L1/L2, 1 hit in TOB L5/L6 ~70K tracks with P T >100 GeV

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 26 Si Strips Tracker Alignment Alignment measured with Survey measurements, Laser System, Cosmics tracks (straight and with magnetic field). Samples: 600K tracks with B=0 T - 4M tracks with B=3.8 T Mean of residual distribution sensitive to modules displacement: Track-based Alignment Algorithms (including Survey constraints) minimize 2 function that depends on residuals Only modules with >30 hits considered: TIB 96%, TID 98%, TOB 98%, TEC 94% Distribution of mean of track residuals with different alignments sets TOBTIBTEC-TOB TIB TID Pixe l “ CRAFTHIP”: geometry obtained from the Hits & Impact Point algorithm applied to CRAFT data RMS 28 µm RMS 26 µm

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 27 Pixels  Noisy Pixels: % → 0% !!  Pixel Cluster charge: close to ideal  Barrel aligned at module level, Endcap aligned at half-disk level RMS 47 µm

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 28 CMS design allows for intervention on a large fraction of the detector Detector opened Nov. 17 th :  Few interventions/repairs of problematic channels (order of ~1%)  ECAL Preshower installation  Completion and commissioning of one RPC Endcap (neg. side)  CMS cooling maintenance  Revision of tracker cooling system after first experience → All ongoing During Shutdown...

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 29 Future Plans  Commissioning Global runs for Preshower, Endcap RPCs  Consolidation of High rate capability  Re-commissioning activities after shutdown period  Optimize performance, increase efficiency and reduce manpower and expertise needed in control room CMS Commissioning 2009 Weekly Global Runs CRAFT09 CRUZET5 CMS Ready For Beam  Repeat Cosmics nominal magnetic field during summer CMS will be closed again with enough contingency for being ready for beam Current LHC schedule: first beams at the end of September, with collisions following in late October. Short technical stop over Christmas. Long 10 TeV run till autumn next year, to provide adequate data for new physics studies ( → results to announce in 2010 ) Magnet tests → Close CMS

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 30 Conclusions  After 20 years of R&D, construction and challenging installation, the CMS commissioning is over! The result is a wonderful detector  All major components fully integrated and operational  Missing channels at % level or less  Synchronization at few ns level or better  Trigger operational and stable DAQ running  CMS exploited at best first LHC data  A one-month-long cosmic ray run with nominal magnetic field allowed the commissioning of final operating conditions (magnet in the cavern) and the tuning of detector performance  LHC setbacks unfortunate, however CMS is using the time to sort out remaining issues, improve on running efficiency, consolidate work-flows CMS is in excellent shape

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 31 SPARES

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 32 Physics Results: Angular distribution Reconstructed angles of cosmic rays → increased acceptance through the CMS access shafts

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 33 Splash Events: correlations Correlation between energy deposits in ECAL and HCAL ~150 TeV deposited in ECAL & ~1000 TeV deposited in HCAL !! Correlation between # of hits in the third ring of DT chambers vs. energy in ECAL

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 34 RPC Muon Chamber y x Single gap working region RPC chamber Efficiency vs impact point (method: DT segment extrapolated on RPC chamber). Lower efficiency points in step of 10 x 10 cm 2 : dead regions induced by spacers. Efficiency reduction at y coordinate = 55 cm RPC is expected.

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 35 DT Muon Chambers Data MC MB4 σ=210µm σ=225µm σ=237µm σ=258µm Wheel -2 Sector 4 MB3 MB2 MB1 DT spatial resolution in de-bunched events: Residuals = x Track – x RecHit Resolution ~200–260 μm Reasonable agreement between data and MC B field degrades MB1 in wheels +/-2

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 36 TAG&PROBE technique Muon trigger studies

DIS2009, Madrid 26 April 2009 – Roberta Arcidiacono 37 Computing and Software Challenges  Test readiness to deal with LHC data taking and analysis work-flow → Full fledge exercise carried out in May 2008 using simulated data Computing challenge: Data transfer, reconstruction concurrent with other LHC experiments to test GRID At the same time: Complete & deploy physics analysis tools Commission “physics analysis paths” from Tier0 → Tier1 → Tier2 Transfer rates during Global Commissioning Runs(different colors – different Tier 1’s) During CRaFT: 600 TB of data volume transferred to Tiers