1. Winter Workshop on Nuclear Dynamics, 2007 1 Heavy Ion Physics with CMS: Day-One Measurements Olga Barannikova for the CMS Collaboration

2. Olga Barannikova Winter Workshop on Nuclear Dynamics, 2007 2 Outline CMS Detector Components, Acceptance, Capabilities Heavy Ion Program in CMS Triggering Advantages of HLT Day-One physics expectations Low-p T tracking PID Capabilities

3. Olga Barannikova Winter Workshop on Nuclear Dynamics, 2007 3 CASTOR T2 Collarshielding Forward Detectors (5.2 <  < 6.5) TOTEM ZDC (5.3 <  < 6.7) (z =  140 m) Beams EM HAD The CMS Detector

4. Olga Barannikova Winter Workshop on Nuclear Dynamics, 2007 4 4T Field Particle Detection in CMS

5. Olga Barannikova Winter Workshop on Nuclear Dynamics, 2007 5 Heavy Ion Events in CMS Pb+Pb event display: Produced in full software framework (simulation, data structures, visualization) Pb+Pb event (dN/dy = 3500) with      -   Pixels Inner Strips Outer Strips

6. Olga Barannikova Winter Workshop on Nuclear Dynamics, 2007 6 From RHIC to LHC Factor 30 increase in energy to √s NN =5.5 TeV Gluon Saturation – even at  =0 High Luminosity Large Cross sections  New high p T reach  Directly identifiable jets  J/ψ, Z 0 and  -family production Baier,hep-ph/0310274 RHIC Vogt, hep-ph/0205330 LHC 

7. Olga Barannikova Winter Workshop on Nuclear Dynamics, 2007 7 Heavy Ion Program @ CMS Hard probesQuarkonia Forward Physics Forward Physics Limiting Fragmentation, Saturation, CGC Ultra-peripheral Collisions – PDF in New Regions of x and Q2 High p T and Quarkonia Jet Quenching, Energy Loss Mechanisms, FF Modifications Calibrated probes of Energy Loss - , Z0, Jet- , Jet-Z0, Quarkonia (J/ ,  ) and Heavy Quarks – Suppression and Recombination Soft Sector Centrality and good Event Selection (N part, N coll ) Charged Particle Multiplicity – Initial State Gluon Densities Azimuthal Asymmetry (Flow) – EoS Spectra + Correlations – Sources, Radial Flow, dE/dx and Quenching

8. Olga Barannikova Winter Workshop on Nuclear Dynamics, 2007 8 Background: dN ch /dy ~ 5000 Jet Reconstruction Jet resolution :    0.032    0.028    16 % pp (pileup subtracted) Jet in Pb + Pb after pileup subtraction CMS NOTE 2006/050 Jet E T ~100 GeV Iterative jet cone-finder algorithm with  -dependent Event-by-Event background subtraction

9. Olga Barannikova Winter Workshop on Nuclear Dynamics, 2007 9 Jet Reconstruction Vardanyan Efficiency, Purity,% Jet Energy Resolution, %  Fragmentation functions Di-jet correlations

10. Olga Barannikova Winter Workshop on Nuclear Dynamics, 2007 10 Quarkonia Kodolova, Bedjidian SPS RHIC LHC?  = 35 MeV/c 2 Charm spectral suppression vs. T CMS - The best experiment for mass spectra measurements of the upsilon family

11. Olga Barannikova Winter Workshop on Nuclear Dynamics, 2007 11 Di-Muon Reconstruction Kvatadze Mironov Z 0 -  can be reconstructed with high efficiency Z 0 production will probe nuclear shadowing and parton energy loss Jet quenching with “calibrated” jets Low background compared to  0 -noisy  - jets Z 0 – jet: Cleaner but lower rates dN/dy ~7000,  > 120GeV in Barrel

12. Olga Barannikova Winter Workshop on Nuclear Dynamics, 2007 12 CMS HLT Physics Enhancement with HLT In HLT: Centrality, Event Plane, Vertex Position, dN/dE T, E jet, Muon Tracks… Statistical Significance – 1 Year Production Rates in Pb+Pb C.Roland, Veres Day-One Measurements 

13. Olga Barannikova Winter Workshop on Nuclear Dynamics, 2007 13 High p T Suppression/Tracking I. Vitev and M. Gyulassy, PRL 89 (2002) Inclusive p T Spectra vs. Centrality  Nuclear Modification Factors (R AA, R cp )  200 GeV/c reach based on Production Rates + HLT C. Roland p T [GeV/c] Resolution (%) Momentum Resolution Efficiency o Fake Rate p T [GeV/c] Efficiency/Fake-rate (%)

14. Olga Barannikova Winter Workshop on Nuclear Dynamics, 2007 14 Global Physics Event by Event dN/d  and dE/d  Hit Counting and Tracklets in Pixels Energy measurements  5.2 (HF) 6.5 (CASTOR) ch Extrapolation from RHIC Silicon Tracker High granularity pixel detectors Pulse height in individual pixels Very low p T reach, p T ~ tens of MeV/c dE(  ) in adc units

15. Olga Barannikova Winter Workshop on Nuclear Dynamics, 2007 15 Elliptical Flow Reaction Plane  = 0.12 rad CMS: RHIC Reaction plane (  R ) x z y x y z Petrushanko

16. Olga Barannikova Winter Workshop on Nuclear Dynamics, 2007 16 Tracking Performance at Low p T Tracker Low p T Tracking Extension with Three Pixel Layers Efficiency Fake Rate Pixel Tracking

17. Olga Barannikova Winter Workshop on Nuclear Dynamics, 2007 17 PID Capabilities dE/dx and Topology (V 0 ): Pb+Pb @ 5.5GeV ~ high-luminosity minimum bias pp @ 14TeV CMS NOTE AN-2006/101 The truncated mean dE/dx vs. p Ferenc Siklér

18. Olga Barannikova Winter Workshop on Nuclear Dynamics, 2007 18 Summary CMS is:  …designed for excellent performance in hard sector  …has unique forward physics capabilities  …a detector with a sophisticated trigger for extended physics reach  ….has surprising ability for global/soft physics  …. all of the above Coverage Jet Physics Quarkonia Z 0 (N ch, E T ) vs.  EbyE physics R AA @ 200 GeV/c In one year of running