1. First CMS Results with LHC BeamToyoko Orimoto, Caltech 1 First CMS Results with LHC Beam Toyoko Orimoto California Institute of Technology On behalf of the CMS Collaboration Lake Louise Winter Institute 16-21 February 2009

2. First CMS Results with LHC BeamToyoko Orimoto, Caltech 2 The CMS Detector Pixels Tracker ECAL HCAL Solenoid Muons Compact, Modular Weight: 12500 t Diameter: 15m Length: 21.6 m EM calorimeter: ECAL PbWO 4 crystal calorimeter High resolution High granularity, >70k crystals Barrel (EB) & Endcap (EE) Hadronic calorimeter: HCAL Brass & scintillator Barrel (HB), Endcap (HE), Outer (HO) Tracker 66M Si pixels & 10M Si strips Superconducting Solenoid Very large, 6m x 13m 3.8T, 1.6 GJ stored energy Muon System Barrel: Drift Tubes (DT) Endcap: Cathode Strip Chambers (CSC) Barrel & Endcap interleaved with Resistive Plate Chambers (RPC)

3. First CMS Results with LHC BeamToyoko Orimoto, Caltech 3 Timeline: First LHC Beams 7-9 September Single shots of beam 1 onto closed collimator 150m upstream of CMS (“beam splash” events) 10 September (Media Day!) Beam 1 circulated in the morning, 3 turns within 1 hour! Beam 2 circulated by 3:00pm, 300 turns by evening 11 September RF system captures beam at evening (millions of orbits) During all these activities, CMS triggered and recorded data ~40 hours of beam to CMS BEAM Collimators 146m CMS Debris Beam Splash Schematic Beam 2, E=450 GeV Beam 1, E=450 GeV CMS The Large Hadron Collider

4. First CMS Results with LHC BeamToyoko Orimoto, Caltech 4 Beam Splash Event Display HCAL energy ECAL energy DT muon chamber hits LHC Tunnel profile visible Longitudinal views Transverse views Single beam shots of 2*10 9 protons onto closed collimators Hundreds of thousands of muons pass through CMS per event

5. First CMS Results with LHC BeamToyoko Orimoto, Caltech 5 Beam Splash: ECAL Energy TOP BOTTOM Enormous amount of energy deposited in calorimeters! ~200 TeV energy deposited in EB+EE > 99% of ECAL channels fired Beam (clockwise) came from plus side. Endcap calibrations were not yet applied (lowest gain photo- detectors are nearest the beam pipe). ECAL Endcaps ECAL Barrel ix iy ii ii Correlation Between Energies in Barrel HCAL and ECAL ~150 TeV in ECAL & ~1000 TeV in HCAL per splash event

6. First CMS Results with LHC BeamToyoko Orimoto, Caltech 6 Beam Halo Muons Beam Halo: Beam Halo: Muons outside of beam-pipe, arising from decays of pions created when off-axis protons scrape collimators or other beamline elements  ME  4ME  3ME  2ME  1 LHC Tunnel Profile Endcap Muon CSC Hit Distribution from Beam Halo Events BEAM 2

7. First CMS Results with LHC BeamToyoko Orimoto, Caltech 7 Beam Halo Muons Endcap muon chambers 3 muons 1 muon Barrel muon drift tubes Endcap muon chamber s Reconstructed Tracks

8. First CMS Results with LHC BeamToyoko Orimoto, Caltech 8 Halo and Cosmic Muon Angles Beam halo muons to make a small angle Cosmic Ray muons pass through the CSCs at a more oblique angle Beam-on distribution consists of two pieces, one resembling cosmic rays and the other matching the beam halo simulation. Angle of Muon Tracks wrt Beam Line beam ON data = combination of beam halo cosmic rays

9. First CMS Results with LHC BeamToyoko Orimoto, Caltech 9 Beam Halo Before and After RF Capture Beam Halo Rates in Muon Endcaps CSC halo trigger rate in the minus endcap as a function of time. First successful capture lasted for 10 min and ended with beam abort HCAL Endcap Energy Before, high rate of energy deposition near beamline. After, beam is cleaner, depositing less energy in HE. BeforeAfter First RF capture of beam time h:m X (cm) Y (cm) HE Peak Energy Location and Amplitude

10. First CMS Results with LHC BeamToyoko Orimoto, Caltech 10 Alignment with Beam Halo Muons Endcap Muon Cathode Strip Chamber Alignment Use tracks passing through overlap of 2 chambers Determine relative pos by requiring consistency between 2 track segments r  position,   z rotation in layer's plane Cross-check against photogrammetry (PG) Track-based alignment accuracy: 270  m r  0.35 mrad  z Achieved with 9 min of LHC beam data (~30k events) Chamber-by-chamber Diff wrt Photogrammetry Before & after track alignment

11. First CMS Results with LHC BeamToyoko Orimoto, Caltech 11 CMS Detector Status Since beginning of September 2008 All installed CMS sub-detectors in global readout routinely All triggers operational Stability of running with all CMS components proven LHC clock and orbit signals tested Synchronization to few ns or better Have continued global data-taking with cosmics CRAFT: Cosmic Run at Full Tesla Detector opening started Nov 17 th Interventions/repairs for problematic channels Installation of Preshower detector

12. First CMS Results with LHC BeamToyoko Orimoto, Caltech 12 CMS Performance with Cosmics collision loss brem radiation ECAL dE/d  x: Experimental data vs Expected stopping power for PbWO 4  Momentum Data vs MC p (GeV/c) CRAFT: Cosmic Run at Full Tesla ~300 M cosmic events collected Field at 3.8T operated for ~1 month Participation from all subsystems Detector performance studies as well as detailed cosmics studies ongoing

13. First CMS Results with LHC BeamToyoko Orimoto, Caltech 13 CMS Performance with Cosmics   /ndof After Tracker Alignment   /ndof Strip Inner Barrel RMS 26  m Pixel Barrel RMS 47  m Pixel & Strip Tracker Alignment: Mean of Residuals Strip Outer Barrel RMS 28  m S/N = ~30 Excellent eff > 99% Si Strip Tracker: Signal to Noise S/N

14. First CMS Results with LHC BeamToyoko Orimoto, Caltech 14 Conclusions After many years of design & construction, CMS is commissioned and has collected first data with LHC Detector performance proven with beam splash, beam halo, as well as cosmics with and without B field. Expect more results, not just with single beam or cosmics, but with collisions!