Status and Prospects of the CMS Experiment at the LHC Darin Acosta University of Florida Including LHC highlights

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 2 The CMS Collaboration n 3000 scientists and engineers are involved in this huge project, coming from 183 institutes in 38 countries spanning Europe, Asia, the Americas and Australasia. n Southeast U.S. collaborating institutes on CMS: u Florida: l Florida International University, Florida Institute of Technology, Florida State University, University of Florida u Mississippi: l University of Mississippi u Tennessee: l Vanderbilt University u Virginia l University of Virginia

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 3 The Large Hadron Collider (LHC) n 7 TeV on 7 TeV proton-proton collider, 27km ring u 7 times higher energy than the Tevatron at Fermilab l Aim was for 5 TeV in 2008 u 100 times higher design luminosity than Tevatron (L=10 34 cm -2 s -1 ) n 1232 superconducting 8.4T dipole T=1.9ºK u Largest cryogenic structure, with 40 ktons of mass to cool n 4 experiments n Start Date: Sept. 10, 2008

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 4 Reasons for the LHC: Puzzles in Particle Physics n The precision of calculations in the Standard Model of particle physics depends on the Higgs mechanism in the theory, which generates mass for particles u But the associated Higgs boson has not yet been directly observed. u Need higher energy and higher luminosity to increase production yield n The Higgs mass must be fine-tuned to extremely high precision, as it receives radiative corrections to its mass in calculations u Protected by Supersymmetry ? l A symmetry sort of like antimatter, but with opposite spin rather than charge (bosons  fermions) l Not observed, so presumably at a higher energy scale u Protected by other new forces/particles? (Z’, W’, technicolor) u Protected by (compactified) extra dimensions? n Any unification of the fundamental forces? n What is the dark matter in the universe ? u Supersymmetry can lead to stable massive neutral particles

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 5 Clues Mass of W , carrier of weak force (radioactivity) Mass of the top quark (heaviest) Mass of the Higgs boson u Nice consistency of direct mass measurements with indirect precision electroweak measurements  both point to a “light” Higgs u Light Higgs indicates new physics must come in for consistency of theory u Light Higgs (<135 GeV) can be accommodated by Supersymmetry PDG, 11/2007

LHC Start-up: Sept.10, 2008 Carlo Rubbia: Nobel laureate and former CERN director who launched the LHC Lyn Evans, LHC Project Leader

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 7 A Brief Diary of LHC Events n Aug. 8 and Aug. 22 Weekends u “Synchronization tests” sent protons through the first arcs of the LHC in both directions, past ALICE and then LHCb experiments u By Aug.22, alternate injections of beam 1 and 2: “…pretty blooming amazing…” n Sun/Mon, 7-8 Sept. u Single shots of beam 1 onto a collimator 150m upstream of CMS. n Tues, 9-Sept u Additional single shots of beam 1 onto a collimator at CMS n Wed., 10 Sept. (Media Day!) u Beam 1 circulated in the morning, 3 turns by 10:40am (1 hour!) u Beam 2 circulated by 3:00pm u 300 turns of beam 2 by 11:15pm n Thurs., 11-Sep. u RF system captures beam at 10:30pm (millions of orbits)

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 8 Sept.10 – Big Media Day

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 9 morning afternoon Beams circulated at injection energy of 0.45 TeV on Sept.10 Separately, no collisions

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 10 Sept.10 orbits n 2 turns of clockwise beam: ~2x10 9 protons

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 11 Sept. 11 Beam Capture No RF Wrong phase Wrong frequency Captured! orbit Time window

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 12 Setback: Friday, Sept.19 n An incident occurred during a powering test of one LHC sector for commissioning beam operation to 5 TeV u Massive helium loss in one arc of the tunnel (2 tons initially), cryogenics and vacuum lost n The cause of the incident was determined to be a faulty electrical connection (“bus bar”) between a dipole and a quadrupole u Mechanical damage occurred u Need to extract and repair dipole and quadrupole magnets in the region n Not enough time to make repairs before winter shutdown  Aim to restart LHC operations mid-2009

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 13 Components of a Collider Detector n Surround the collision point with instruments in order to identify the types of particles and their energy or momentum to reconstruct collisions Muon detectors Magnet Calorimeters Tracking detectors

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 14 The Compact Muon Solenoid Experiment PbWO 4 Crystals Muon chambers Silicon Strip & Pixel Tracker 4T solenoid Hadronic calorimeter Brass/Scintillator Forward calorimeter Conceived 1992

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 15 And in reality… March 2007 Hadron calorimeter being inserted (for energy measurements) magnet muon detectors

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 16 Preassembled muon detector structures lowered into the cavern Endcap disks: January 2007 to January 2008 Barrel wheels: Jan. – Oct ( ton structures!)

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 17 CMS Electromagnetic Crystal Calorimeter Barrel production and installation completed 27 July 2007 Endcap production complete and inserted 1 August 2008  76K PbWO 4 crystals for fine electron/photon energy measurements More crystals (in volume or number) than in all previous HEP experiments combined

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 18 Silicon Strip Tracker, Dec 2007 Cabling completed March m 2 of sensor coverage, 11M strips (Charged particle tracking) 10 times more coverage than CDF silicon detector

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 19 Installation of the Pixel System, August 2008 n A 66 megapixel “camera” ! u Makes precise measurements of charged particle impact parameters to tag particles with a small but finite lifetime

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 20 CMS Completed! August 25, 2008 – 16 years after its Letter of Intent 20 Ready for the LHC

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 21 Detector Commissioning Exercises n In Fall 2006 we had the first magnet test and data- taking with a slice of the experiment for about 2 months n Since May 2007, periodic exercises of 3-10 days have been devoted to global commissioning exercises with installed detectors and electronics underground, ultimately using final power/cooling in the underground experiment cavern and the service cavern u Balancing the need to continue installation and local commissioning activities with the need for global system tests n The incremental goals from one run to the next focus on increased complexity and increased scale. n Frequency of runs increased as we headed to LHC start- up, where CMS ultimately became a 24/7 running experiment ready for beam

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 22 Fraction of CMS Systems in Global Runs Muon Cabling complete, final power & cooling become available Cooling ready for Strip Tracker Pixel system and ECAL endcaps installed

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 23 Cosmic ray muons used as probe of detector performance during Global Runs (no beam!) Total rate is about 350 Hz at 100m depth (about 1% of rate on surface of Earth)

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 24 Global Detector Readout Tracker ECAL HCAL Muon System  Muon signals traced through muon system Strip Tracker (and pixels when close to beam pipe) ECAL HCAL  Requires synchronization of all electronic signals  Global track fit can be used for alignment and detector performance studies 24

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 25 Tracks crossing the pixel tracking system n Rate < 0.1 Hz n Need a LOT of data to align sensors n But tracks going through the small pixel detector resemble those from collisions 25 First cosmic tracks with Pixels

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 26 The Excitement of the First LHC Beam Measurements at CMS! ( September 2008 )

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 27 Beam Splash Events n Beam with 2x10 9 protons dumped onto a target (collimator) 150m upstream of CMS u Sept. 7,9,10,18 n Leads to a “tsunami” wave of O(100K) muons coming down the tunnel! u A far cry from the single cosmic muon events… n CMS was ready for this challenge given its extensive commissioning program beforehand u Electronic triggers and data acquisition worked well CMS 146 m TAN TCTV TCTH MBRC TCLP debris p

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 28 Different projections of a “splash” event HCAL energy ECAL energy DT muon chamber hits particle debris Inner silicon tracking systems kept OFF Longitudinal views Transverse views

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 29 Halo Muons (from proton beams passing through CMS) ME  4ME  3ME  2ME  1 Muons associated with beam (but outside beam pipe) arising from the decays of pions created when off-axis protons scrape collimators or other elements along beamline A useful tool for detector alignment and time synchronization Note shape of tunnel  More details on triggering on these muons, and their rates, in presentation by J.Gartner

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 30 Now: Cosmic Run at Four Tesla (CRAFT) n In the rush to install the last components of CMS and to close the experiment, CMS did not manage to re- commission its magnet to 3.8T underground, nor record a significant amount of data at full field before LHC start-up u Magnet was commissioned in 2006 while experiment was in the surface assembly hall u Only short tests up to 3T underground took place n Now without the LHC for the rest of 2008, CMS continues its program with a month-long exercise to collect cosmic muons with B=3.8 T u Aim for 300M cosmic events for analysis, equaling the sample size we have collected at zero field u Run 24/7 for 1 month to refine operations even without beams to improve readiness for LHC next year

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 31 CRAFT Statistics, Oct.16 – 29 n In 2 weeks surpassed 150M events, 50% of our goal u Reached 100% data-taking efficiency over 24h [average 55%] This week: 24h run Tue-Wed 16h run Sat-Sun

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 32 F=q(v×B) From which p = qBr

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 33 Cosmic Charge Ratio Measurement CMS NOTE-2008/016 DT Muon system measurement Aim to improve upon 2006 measurement using CRAFT data and full detector

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 34 Physics Preparation: Calibration and Alignment n Alignment u Need the strip tracker modules aligned to about 20  m precision, whereas the placement precision for structures is about 1mm u Significant progress using cosmic muons to align components l Better than 50  m precision for about half of central Tracker u Will improve with CRAFT data and with LHC collision data n Energy calibration: u Hadron calorimeter: 5% precision confirmed with cosmic rays u Electromagnetic calorimeter (Central region): l 0.3% precision for 1/4 of barrel (dedicated beam tests) l % on remaining 3/4 from cosmic rays u Methods to cross-check or improve precision using first LHC collisions l Isolated charged particles with momentum measured by Tracker l Average energy flow l “Resonances” (particles decaying to photons, electrons) n Expect sufficient precision for LHC startup physics !

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 35 Glimpse of Discovery Physics: Z′→ee, µµ Tevatron reach ? Possible reach for 2009 ? simulated New force search

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 36 Glimpse of Discovery Physics: Supersymmetry n Large missing momentum from escaping invisible particles u Classic signature of minimal supersymmetric models with a dark matter candidate n Energetic “jets” from supersymmetric particle decays n Similarly extend reach well past the Tevatron simulated

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 37 Summary of Discovery Prospects in SUSY u Squark and gluino masses up to about 2 TeV with 10 fb -1, 2.5 TeV ultimately at LHC Various search topologies Tevatron reach ? 2009 reach ?

30 October 2008 The CMS Experiment - SESAPS08 - D.Acosta 38 Summary & Outlook n The CMS experiment was completed and ready in time for the LHC this year u Definitely a non-trivial accomplishment! u Already made maximum use of the limited time with LHC beams n The LHC setback is disappointing, but not surprising given the complexity and scale u The rapid pace of LHC start-up commissioning bodes well for next year! n CMS is focused on collecting a large cosmic dataset with its magnet at full strength (3.8T) for the next month u Continue exercising experimental procedures to improve readiness for 2009 u Refine knowledge of detector performance in preparation for physics studies n Even more eagerly awaiting to launch the LHC, and studying physics at the TeV frontier!