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CMS Heavy Ion Physics

CMS Heavy Ion Physics. Edwin Norbeck University of Iowa. Energy for Pb + Pb at LHC. Beam is 7 TeV/charge  s = 5.5 TeV/nucleon pair or = 1140 TeV total. Total energy, mc 2 , in center of mass is 30  energy at RHIC . Energy density ~  2 900  energy density at RHIC.

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CMS Heavy Ion Physics

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  1. CMS Heavy Ion Physics Edwin Norbeck University of Iowa

  2. Energy for Pb + Pb at LHC • Beam is 7 TeV/charges = 5.5 TeV/nucleon pairor = 1140 TeV total. • Total energy, mc2, in center of mass is 30  energy at RHIC. • Energy density ~ 2900  energy density at RHIC 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  3. Large Hadron Collider at CERN 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  4. What To Expect from LHC • LHC (Large Heavy ion Collider) is expected to provide pA and AA collisions. • Energy: 7 TeV/charge • 6 weeks/year • First heavy ion run in March 2007 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  5. 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  6. The experiments ALICE: dedicated HI experiment, 900 collaborators CMS: pp experiment with approved Heavy Ion program, <50 HI physicists (out of 2000) 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  7. 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  8. Pile-up problems • For CMS • None for Pb + Pb (125 ns between bunches) • None for p + p (25 ns between bunches) • For Ca + Ca should reduce luminosity by 10 (25 ns between bunches) • ForALICE • None for Pb + Pb • For p + p reduce luminosity by factor of 104 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  9. CMS: High pt edge of HI physics 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  10. 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  11. Stretching CMS Pb-Pb mm Detector designed for pp. However due to flexible design offers unique capabilities for AA 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  12. Some CMS Assets • CMS has excellent muon detection capabilities: • |h|<1.3 for barrel and |h|<2.4 with endcaps. • Good mass resolution: 46 MeV for the Upsilon. • Efficient suppression of background from p/K decays: • Electromagnetic calorimeter at 1.3 m from beam axis. • PT threshold at 3.5 GeV/c for a single muon to reach the m-chambers. • Large calorimeter coverage with good jet reconstruction capabilities. 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  13. Selected Physics Topicsfirst physics studies by CMS • Event Characterization • Quarkonium Production: Upsilon and J/Y in the barrel • Z detection • Jet Production: • Single/Double jet ratios, jet quenching • Z and g tagged jets • Ultra-Peripheral Collisions: gg and g-Pomeron Muon detector Calorimetry 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  14. m m t n p k p freeze-out hadronization chiral symmetry thermal equilibrium chemical equilibrium deconfinement hadrons mixed plasma partons thermalisation z Particle production in Heavy Ion collision, signs of QGP • mass and width of resonances (r, w) • thermal photons or dileptons (e+e-,m+m-) • strangeness enhancement (K,f, L, X, W) • energy loss of initial partons (jet quenching) • suppression of heavy-quark bound states (J/y , ¡’s  m+m-) 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  15. Tracking 60 Detector Pitch mm • Developed for dNch/dy=8000 and dN0/dy=4000. • Track only particles with tracks in m detector. • Use m-chambers tracks as seeds. • Use only tracking detector providing 3D space points. MSGC 200 50 MSGC 240 Silicon 147 40 Occupancy (%) 30 20 10 0 60 70 80 90 100 110 120 Radius of tracking layer (cm) 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  16. Quarkonia Cross Sections Production Cross Sections for CMS studies • A scaling law: sAA= A2a spp • spp from CDF @ 1.8 TeV extrapolated to 5.5(7) TeV.(central 2300) • a=0.9(0.95) for J/Y (Upsilon). 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  17. Most products at small angles Simulations for pp show average per event of: 760 GeV into 3 < < 5 (HF) 0.8° to 5.7° 100 GeV into -3 < < +3 (rest of CMS) In HF most of the 760 GeV is at small angles. For Pb + Pb ? 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  18. 2.5 mm EM HAD 2.5 mm TC HF Longitudinal Segmentation 0.6 mm quartz fibers in iron TC (30 cm) HAD (143 cm) EM (165 cm) Half a million quartz fibersviewed with 2400 phototubes 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  19. Shower and jets in HF (forward calorimeter) • Radius (80%) of e.m. shower 2.5 cm • Radius (80%) of hadron shower 5 cm • For jet radius |h| = 0.3 |h|(jet) radius in HF 3 (5.7°) 35 cm 4 (2.1°) 14 cm 5 (0.77°) 4.7cmh -ln tan(/2)  rapidity for p >> m tanh(h) = cos () 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  20. Higgs “tagging” jets • “Heavy” Higgs 2mZ or 2mW < mH< 1 TeV • qq  (WW, ZZ  H)jj • For jets 2 < < 5 • But 3 < < 5 seen only in HF 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  21. Response to Electrons and Pions • HF responds linearly within 1% to electrons in the energy range tested (6 – 200 GeV). The pion (neg) response is highly nonlinear. 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  22. 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  23. Beam-beam interactions • Hadronic nuclear interactions • Electromagnetic dissociation • Ion is excited by a - nucleon interaction (mostly by the giant dipole resonance) and subsequently decays. • Electron capture to form H-like ion • A two-photon process creates an electron-positron pair with the electron retained in an atomic orbit (mostly the K-shell). • Magnetic-monopole production? 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  24. 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  25. Summary • LHC will be a natural continuation of the series of Heavy Ion accelerators • CMS will have unique capabilities at the high transverse momentum frontier • , Z0, g, high pt jets • CMS can provide a natural place to do these measurements in the late-RHIC and post-RHIC era • Complementary to RHIC 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

  26. 6th Workshop on Heavy Ion Physics with CMS detector at the LHC High pt heavy ion physics at the LHC Massachusetts Institute of TechnologyFebruary 8-9, 2002Cambridge, MA http://bolek.lns.mit.edu or wyslouch@mit.edu Office (617) 253-5431 Cell (781 354-5023 18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa

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