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Studies of QCD Matter at the Large Hadron Collider

Studies of QCD Matter at the Large Hadron Collider. Russell Betts UIC. Experimental Study of Ultra-Relativistic Nucleus Nucleus Collisions. BNL AGS (1986)  s NN  5 GeV/u O+O, Si+Si, Au+Au. CERN SPS (1986)  s NN  20 GeV/u O+A, Pb+Pb. BNL RHIC (2000)  s NN  200 GeV/u

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Studies of QCD Matter at the Large Hadron Collider

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  1. Studies of QCD Matter at the Large Hadron Collider Russell Betts UIC Russell Betts - UIC

  2. Experimental Study of Ultra-Relativistic Nucleus Nucleus Collisions BNL AGS (1986) sNN  5 GeV/u O+O, Si+Si, Au+Au CERN SPS (1986) sNN  20 GeV/u O+A, Pb+Pb BNL RHIC (2000) sNN  200 GeV/u Au+Au, d+Au, Cu+Cu Russell Betts - UIC

  3. What Do Multiplicities Teach Us? 0 fm/c 2 fm/c 7 fm/c >7 fm/c Time Evolution of Collisions Parton DistributionsNuclear Geometry Nuclear Shadowing Parton Production& Reinteraction QCD Matter Jet FragmentationFunctions Chemical Freezeout &Quark Recombination Hadron Rescattering Thermal Freezeout &Hadron Decays Russell Betts - UIC

  4. Models prior to RHIC Energy Dependence of Particle Production dN/dh Lower than Most Expectations Scales with Npart (not Ncoll) NTot ~ 8000 + Average Transverse Energy Energy density ~5 GeV fm–3 (Nucleon ~ 0.3 GeV fm–3) Partonic Degrees of Freedom Russell Betts - UIC

  5. Exploring the Phase Diagram Lattice QCD Tcrit~ 150 MeV • T and mB from Thermal Model Fits to Particle Ratios • AGS T=125 MeV mB= 540 MeV • SPS T=170 MeV mB = 270 MeV • RHIC T=170 MeV mB = 27 MeV Russell Betts - UIC

  6. z Reaction plane y x Results for Collective (Elliptic) Flow sQGP wQGP Hydrodynamic Limit of Flow at RHIC Strongly Interacting Fluid Russell Betts - UIC

  7. High pT Suppression (Medium Effect) STAR Suppression of High pT Particles Relative to pp Reference Absorption of Away-Side Jet Russell Betts - UIC

  8. Gluon Saturation Effects • Small x & Large A • Large occupation number • Coherentstate • Saturation momentum Qs (x) x Suppression at Forward Rapidity (Small x) – Evidence for Gluon Saturation – Color Glass Condensate d+Au Brahms Russell Betts - UIC

  9. Summary of RHIC Results • The Matter is Surprisingly Strongly (Re)Interacting • Slow Growth of Multiplicity with Energy ( NOT Ncoll*pp) • Chemical Equilibrium of Hadronic Species • Very Large “Flow” – Hydrodynamic Limit • Strong Suppression of Particles with Relatively High pT (Not in Cold Matter of d+Au) • Saturation Effects at Small x • Much Still to Do: • Quarkonium Studies – Color Screening • Particle Correlations vs Collision Geometry • Modification of Fragmentation Functions • Etc etc etc …………………… Rare Probes Need Increased L or sqrt(s) RHIC II (New Detectors) ($$$$) or LHC Russell Betts - UIC

  10. CERN Large Hadron Collider pp Pb+Pb Russell Betts - UIC

  11. Z0  J/ A New Viewpoint for QCD Matter at LHC • Factor 30 Higher sqrt(s) than RHIC • Initial state dominated by low-x components. • Abundant production of variety of perturbatively produced high pT particles for detailed studies • Higher initial energy density state with longer time in QGP phase • Access to new regions of x Russell Betts - UIC

  12. CMS at the LHC Russell Betts - UIC

  13. SUPERCONDUCTING COIL Total weight : 12,500 t Overall diameter : 14.6 m Overall length : 21.6 m Magnetic field : 4 Tesla Silicon Microstrips Pixels The CMS Central Region CALORIMETERS ECAL HCAL Scintillating PbWO4 crystals Plastic scintillator/brass sandwich IRON YOKE TRACKER MUON ENDCAPS MUON BARREL Drift Tube Resistive Plate Cathode Strip Chambers (CSC) Chambers (DT) Resistive Plate Chambers (RPC) Chambers (RPC) Russell Betts - UIC

  14. CMS Detector (Augmented) Forward Detectors CASTOR (5.32 << 6.86) TOTEM Collar shielding (5.32 << 6.86) T2 ZDC (z = 140 m) EM HAD Beams Russell Betts - UIC

  15. Particle Detection in CMS Russell Betts - UIC

  16. CMS – Above and Below Ground Russell Betts - UIC

  17. SX5 and UXC CMS caverns inaugurated Feb. 1st 2005 250,000 m3 material removed Main cavern dimensions: 53m x 27m x 24m Modular design can be fully assembled and tested in surface hall (SX5), then lowered into experimental cavern (UX5) within 4 months Frank Wilczek Russell Betts - UIC

  18. 48M pixels 10M strips Pixels Barrel: 3 layers Forward: 2 layers 100x150 m2 pixels Microstrips Barrel: 10 layers (single- and double-sided) Forward: 9 layers 1 GeV central track ~ 15 hits Overall 210 m2 of silicon || < 2.4 Silicon Inner Tracker 2.4 m 5.4 m Russell Betts - UIC

  19. Si Strip Modules Russell Betts - UIC

  20. Tracker Inner Barrel Assembly Russell Betts - UIC

  21. ECAL (PbWO4 - APD Readout) Russell Betts - UIC

  22. 36 Supermodules Dee 4 Dees 138 Supercrystals ECAL Assembly Russell Betts - UIC

  23. HCAL Russell Betts - UIC

  24. HCAL Shells for HE readout boxes installed. HB source calibrated by May-2005 HE- by Aug 2005, HE+ by Nov 2005 HF in Bat. 186. Start ‘burn-in’ of both HF in mid-2005 First elements to be lowered into UX Russell Betts - UIC

  25. Muon System Russell Betts - UIC

  26. Barrel Muon System LEGNARO(MB3) 56/70 end in Dec TORINO(MB4) 6/40 end in Apr. 06 AACHEN(MB1) 59/70 end in Sept CIEMAT(MB2) 54/70 end in Sept Yoke wheel YB+2: 34 chambers installed Russell Betts - UIC

  27. Endcap Muon System Russell Betts - UIC

  28. Status and Schedule • Civil Engineering: USC delivered Aug 04, UXC delivered Feb 05. Civil Engineering is off the Critical Path • Magnet:All 5 coil modules are at CERN. Swivelling in June 2005. End electrical tests by end-05. • HCAL, Muons : Construction on schedule and well advanced. TO WATCH: • ECAL:Crystals production, contracts ready to be placed with two vendors. Need to generate float in ‘ready for installation’ (rfi) milestone. • TRACKER: Rate of assembly of modules, schedule andintegration. Need to generate float in rfi. • CMS* initial detector will be ready and closed for beam on 1 July 2007. *ECAL Endcaps and Pixels will be installed during Winter 2007 shutdown in time for physics run in 2008. Heavy Ions in 2008 Russell Betts - UIC

  29. Heavy Ion Physics with CMS Adana-Turkey, Athens, Basel, CERN, Demokritos, Dubna, Ioannina, Kent State, KFKI Budapest, Kiev, LANL, Lyon, MIT, Moscow, Mumbai, N. Zealand, Ohio, Protvino, PSI, Rice, Sofia, Strasbourg, Tbilisi, UC Davis, UIC, U. Iowa, U Kansas, Warsaw, Yerevan Russell Betts - UIC

  30. Detector Coverage Large Range of Hermetic Coverage in h, x and Q2 Unique Forward Capability Abundant High pT Probes, Jets, J/, , Z0 Russell Betts - UIC

  31. Tracker ECAL Tracker in HI Environment Central Pb+Pb Event dN/dh=5000 (HIJING+OSCAR+IGUANA) >50,000 Charged Particles – BUT Pixels are <2% Occupied (Key to Successful Tracking) Russell Betts - UIC

  32. Preliminary Charged Multiplicity: dNch/d a la PHOBOS • Pixels have High Granularity, Located near Interaction Region (r1 = 4 cm) • Use Summed Pulse Height Measurement in Reconstructed Clusters to Remove Hits from Background Sources (Secondaries, Looping Tracks) • Can Measure Very Low pT Particles Single layer hit counting in innermost pixel barrel layer cosh  dependence of SumADC Chadd Smith Russell Betts - UIC

  33. Track Reconstruction pT resolution (pT/pT) impact parameter || < 0.7 HIJING + GEANT + ORCA – C. Roland efficiency and fakes Track finder based on Kalman filtering method Algorithms exist for primary vertex finding, seed generation, track propagation, trajectory smoothing, and regional tracking High reconstruction efficiency and low fake rate even at high track density Russell Betts - UIC

  34. 100 GeV Jet + Pb+Pb Event EM+Hadronic Energy Hijing + 100 GeV Jet Pair Russell Betts - UIC

  35. HIJING (generator level, acceptance of HF and CASTOR) - C.Teplov Global Physics from Calorimeter HF CASTOR Impact Parameter Correlation with Calorimeter Etot ET Flow from Azimuthal Asymmetry <Day 1 Measurement sQGP or wQGP ?? Russell Betts - UIC

  36. Energy resolution Jet Reconstruction Efficiency, Purity Measured Energy PYTHIA (100 GeV jet) + HIJING (PbPb, dN/d=5000) + full GEANT - I. Vardanyan, O.Kodolova -Resolution -Resolution Sliding Jet Cone Algorithm Used for Background Subtraction Energy Resolution for 100 GeV Jets is  16% Russell Betts - UIC

  37. Longitudinal momentum fraction z along the thrust axis of a jet: pT relative to thrust axis: Jet Fragmentation C. Roland Fragmentation function for 100 GeV Jets embedded in dN/dy ~5000 events. Use charged particles and electromagnetic clusters P.Yepes Using ECAL clusters~0 in CMS Russell Betts - UIC

  38. , Z0 jet <E>=0 GeV <E>=4 GeV <E>=8 GeV Background # Events/4 GeV Isol. 0+jet ET/0-ETJet (GeV) Balancing  or Z0 vs Jets Estimated Event Samples in 1 month Pb+Pb at 1027cm-2s-1 Russell Betts - UIC

  39. Quarkonia in CMS Yield/month (with 50% duty factor) J/  family sM = 60 MeV Russell Betts - UIC

  40. L1 HLT Data Acquisition and Trigger Two-level DAQ/Trigger architecture L1: Low-level hardware trigger Muon track segments Calorimetric towers No tracker info Output rate = few-10 kHz HLT: online farm Replaces traditional L2, L3, etc. Refit muon and calorimeter information, and add tracker info Output rate = 50 Hz Data rate approx. 2-5 MB/event (vs. 1 MB for pp)  100-200 MB/second written to tape Typical CMS Russell Betts - UIC

  41. Main Types of Trigger Required by Physics • multiplicity/centrality:”min-bias”, “central-only” • high pT probes: muons, jets, photons, quarkonia etc. High Occupancy but Low Luminosity • many low level trigger objects may be present, but less isolated than in p+p. Level 1 may be difficult for high pT particles • L1 in AA has larger backgrounds than in pp due to underlying event • we can read most of the events up to High Level Trigger and do partial High Level Trigger can do a better job than L1 ! High Level Trigger (HLT) Russell Betts - UIC

  42. Online farm Online farm Improvement Acceptance x2.5 h pT Illustration Of Online Farm Power: Low pTJ/ψ See CMS Analysis Note 2004/02 • Detection of low pT J/ψ requires efficient selection of low momentum, forward going muons. Simple hardware L1 dimuon trigger is not sufficient Without online farm (HLT) With online farm (HLT) Russell Betts - UIC

  43. (5.32 < η < 6.71) (5.32 < η < 6.86) Forward Detectors: CASTOR and TOTEM ZDC (z =  140 m) • Near Hermetic coverage (out to |η|<7 with CASTOR) • Physics • Centrality • Nuclear PDFs - particularly gluon distributions • Momentum fractions x ~ 10-6 – 10-7 at scales of a few GeV2 in pp • Diffractive processes (10-20% of total cross section at high energies) • Limiting Fragmentation • Peripheral and Ultra-Peripheral collisions • DCC, Centauros, Strangelets …… CASTOR Coverage Russell Betts - UIC

  44. CASTOR Prototype and Tests http://cms.doc.cern.ch/castor/ Russell Betts - UIC

  45. b 2R ~ 15 fm Zero Degree Calorimetry for CMS 100 cm of space available (9.6 x 12.5 x 100 cm) Quartz fiber/tungsten plates EM section segmented horizontally, HAD section longitudinally Luminosity detector in 2nd 10 cm Improves resolution at large b Readout through HF electronics – signals available for L1 trigger EM HAD Lum Beams Beam pipe splits ~140 m from IR Spectators Participant Region Spectators Russell Betts - UIC

  46. ZDC Simulations Megan Lehnherr, Michael Murray, Chadd Smith + Daniel Elvira, Boaz Klima Early product of FNAL LHC Physics Center 1 TeV Neutron hits ZDC Russell Betts - UIC

  47. People and Institutions • Russia: Moscow State University, Dubna • France: Lyon • Georgia: Tbilisi • Hungary: KFKI Budapest • India: Mumbai • New Zealand: Auckland • Greece: Athens, Demokritos, Ioannina • USA NP: Rice, UC Davis, Kent State, LANL, MIT, Ohio, UIC, U Iowa, U Kansas • Turkey, Adana • In general: increased interest due to developments at RHIC and our progress in evaluation of capabilities • Presently ~15-20 people involved directly in studies/discussions etc. • Expect to grow to ~100 by the time LHC starts, ~50 from the US, including PostDocs and Graduate Students Russell Betts - UIC

  48. US Funding Progress (I) • Slow Negotiations with DoE Nuclear Physics • RHIC is large piece of nuclear physics budget • Daily difficulties with supporting the program, competing needs of different experiments, HI vs spin pp program etc – even before FY06 budget !! • BUT: there is a need to plan for the future: • RHIC luminosity upgrades • Detector upgrades, possible new detectors • LHC proposals: ALICE, ATLAS, CMS • 2004 NSAC was asked to form a sub-committee to evaluate whole relativistic heavy ion program. • Recommendation #2 – “The LHC will open up a new regime in relativistic heavy-ion physics with significant opportunities for new discoveries. The Subcommittee recommends that: • Participation in the LHC should become a new component of the US Heavy Ion program • This participation should receive comparable investment priority with each of the two near term upgrade programs for the two large RHIC detectors” Russell Betts - UIC

  49. US Funding Progress (II) • US DoE Nuclear Physics Request • People and equipment for High Level Trigger farms ($3.9M) • Construction of ZDC ~$0.4M • Permission to participate in the program (~30 PhD+15 GS by 2007) • Later M&O with main “service” contribution going towards DAQ/HLT/Computing • The FY06 Budget • NP –8.4%. RHIC small experiments terminated. Running threatened. • NSAC Panel to revisit Long Range Plan – June Report? • But they didn’t say NO ! • Michael Murray (U Kansas) gets NSF Career Award to prototype CMS ZDCs • NP groups allowed to reprogram operating funds to underwrite CMS activities. • We are optimistic and believe that CMS offers the BEST possibilities for exciting heavy ion physics with the LHC Russell Betts - UIC

  50. Summary and Outlook LHC will Extend Energy Range - in Particular High pT Reach - of HI Physics to Provide a New Window on QCD Matter CMS Detector offers Superb Capabilities • Full calorimeter coverage • Superior momentum resolution due to 4T magnetic field • High mass resolution for quarkonia • Centrality, multiplicity, spectra, energy flow to very low pT • No modification to detector hardware • New High Level Trigger (HLT) algorithms for HI • Zero Degree Calorimeter, CASTOR and TOTEM provide unique access to forward physics Russell Betts - UIC

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