CMS Heavy Ion Physics Edwin Norbeck University of Iowa

18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa2 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 ~   energy density at RHIC

18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa3 Large Hadron Collider at CERN

18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa4 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

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6 The experiments CMS: pp experiment with approved Heavy Ion program, <50 HI physicists (out of 2000) ALICE: dedicated HI experiment, 900 collaborators

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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) For ALICE None for Pb + Pb For p + p reduce luminosity by factor of 10 4

18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa9 CMS: High pt edge of HI physics

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18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa11 Stretching CMS Pb-Pb 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 Iowa12 Some CMS Assets CMS has excellent muon detection capabilities: –||<1.3 for barrel and ||<2.4 with endcaps. –Good mass resolution: 46 MeV for the Upsilon. –Efficient suppression of background from /K decays: Electromagnetic calorimeter at 1.3 m from beam axis. P T threshold at 3.5 GeV/c for a single muon to reach the -chambers. Large calorimeter coverage with good jet reconstruction capabilities.

18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa13 Selected Physics Topics first physics studies by CMS Event Characterization Quarkonium Production: Upsilon and J/in the barrel Z detection Jet Production: –Single/Double jet ratios, jet quenching –Z and  tagged jets Ultra-Peripheral Collisions:  and - Pomeron Muon detector Calorimetry

18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa14 p n z partons plasma mixed thermalisation hadronization freeze-out chiral symmetry thermal equilibrium chemical equilibrium deconfinement  k   t hadrons mass and width of resonances () thermal photons or dileptons (e + e    +   ) strangeness enhancement (K  energy loss of initial partons (jet quenching) suppression of heavy-quark bound states (J/, ’s  +   ) Particle production in Heavy Ion collision, signs of QGP

18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa15 Tracking Developed for dN ch /dy=8000 and dN 0 /dy=4000. Track only particles with tracks in  detector. Use -chambers tracks as seeds. Use only tracking detector providing 3D space points. Occupancy (%) Detector Pitch  m MSGC 200 MSGC 240 Silicon 147 Radius of tracking layer (cm)

18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa16 Quarkonia Cross Sections  A scaling law:  AA = A 2  pp   pp from 1.8 TeV extrapolated to 5.5(7) TeV. (central 2300)  for J/ (Upsilon). Production Cross Sections for CMS studies

18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa17 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 mm TC (30 cm) HAD (143 cm) EM (165 cm) HF Longitudinal Segmentation EMHAD TC 0.6 mm quartz fibers in iron Half a million quartz fibers viewed with 2400 phototubes

18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa19 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 || = 0.3 ||(jet) radius in HF 3 (5.7°) 35 cm 4 (2.1°) 14 cm 5 (0.77°) 4.7cm   -ln tan(/2)  rapidity for p >> m tanh() = cos ()

18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa20 “Heavy” Higgs 2m Z or 2m W < m H < 1 TeV qq  (WW, ZZ  H)jj For jets 2 < < 5 But 3 < < 5 seen only in HF Higgs “ tagging ” jets

18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa21 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.

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18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa23 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?

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18th Winter Workshop on Nuclear Dynamics 01/26/02 Edwin Norbeck University of Iowa25 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 –, Z 0, , 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 Iowa26 6 th Workshop on Heavy Ion Physics with CMS detector at the LHC Massachusetts Institute of Technology February 8-9, 2002 Cambridge, MA or Office (617) Cell ( High p t heavy ion physics at the LHC