Heavy-Ion Program in CMS at the Large Hadron Collider

1. Heavy-Ion Program in CMS at the Large Hadron Collider Outline 1. Most Important results from RHIC 2. LHC & CMS 3. Heavy-ion program at LHC 4. Korean contributions to CMS so far 5. Preparation of CMS heavy-ion program in Korea Byungsik Hong Korea University

2. Motivation of HI Collisions Investigating the QCD prediction of a deconfined (& chiral symmetry restored) high-energy-density phase of nuclear matter High-energy nuclear collisions willcompressandheatthe heavy nuclei so much that their individual protons and neutrons overlap and lots of pions arise, creating theQuark-Gluon Plasma (QGP) QGPis thought to have existed ten millionths of second after theBig Bang; creating the primordial matter of universe in the laboratory, Little Bang. KIAS Workshop on LHC

3. Lattice QCD Phase transition is expected in a strongly interacting matter, but not so close to the Stefan-Boltzmann limit. KIAS Workshop on LHC

4. Relativistic Heavy-Ion Machines KIAS Workshop on LHC

5. SIS300 Phases of Nuclear Matter KIAS Workshop on LHC

6. Brookhaven National Lab. in New York • Circumference: 3.83 km • First collision: 2000 • 100A GeV Au+Au(2X1026/cm2/s) • 250 GeV p+p(2X1032/cm2/s) Relativistic Heavy Ion Collider KIAS Workshop on LHC

7. Hadron jet q q Hadron jet QGP Probes • Expectation • quarks and quarkonium states may respond differently to a plasma compared to ordinary nuclear matter • Hard Probes • Formed in initial collisions with high Q2 • Calculable in pQCD given • Parton structure function • Hard scattering rate • Fragmentation function KIAS Workshop on LHC

8. Partonic Energy Loss in QGP • Partons are expected to loose energy via gluon radiation in traversing a QGP(jet quenching) • Hadrons above pT > 2 GeV expected to be from jet fragmentation • Look for a suppression of leading hadrons in that pT region KIAS Workshop on LHC

9. Suppression PHENIX, PRL 91, 072301 (2003) • strong suppression in π0: • decreasing with pT • factor 6 at pT > 6 GeV/c • similar suppression in charged hadrons • RAA slightly higher at intermediate pT due to protons • discrepancies in charged RAA between experiments • Glauber calculations? • NN-reference? • better consistency between STAR and PHENIX for central/peripheral! KIAS Workshop on LHC

10. Initial state: gluon saturation? CGC? Final state: parton energy loss? How to discriminate? Turn off final state  d+Au collisions Initial vs. Final State Effect KIAS Workshop on LHC

11. Centrality Dependence Au + Au Experiment d + Au Control Experiment • Dramatically different and opposite centrality evolution of Au+Au experiment from d+Au control one. • Jet Suppression is clearly a final state effect. Final Data Preliminary Data KIAS Workshop on LHC

12. trigger Jet Correlation Phys Rev Lett 90, 082302 KIAS Workshop on LHC

13. PHENIX Preliminary 2σ syst 1σ syst Away-Side Jet Correlation at Low pt KIAS Workshop on LHC

14. Far Side Near Side Interpretation Discovery of the color shockwave? PHENIX Preliminary KIAS Workshop on LHC

15. z transverse plane (at midrapidity) reaction plane time y x v1<0 v1 >0 sideward flow px = v1 pt v2<0 v2 >0 elliptic flow RN=(1+ v2)/(1-v2) Elliptic Flow KIAS Workshop on LHC

16. x z η∼0 η∼3 η∼-3 Anisotropic Flowv1, v2, v4, … h~3 h~-3 h~0 Reaction plane Spectators Spectators v2 = 15% v2 = 15%, v4=4% 1.5 Y 1 Out-of-plane 0.5 In-plane X v2 = 7% v2 = 7%, v1=+7% v2 = 7% v2 = 7%, v1=-7% KIAS Workshop on LHC Isotropic emission

17. Directed Flow v1 • Consistent among RHIC Expts. • Shape in forward rapidity agree with low energy data by NA49 • Elongated shape near midrapidity STAR, PRL92, 062301 (2004) NA49, PRC69, 034903 (2003) M. Belt-Tonjes for PHOBOS (QM04) H. Masui for PHENIX (QM04) KIAS Workshop on LHC

18. v2 vs Rapidity STAR M.B. Tonjes for PHOBOS (QM04) v2 is positive: v1 and v2 are in the same plane KIAS Workshop on LHC

19. Quark Recombination or Coalescence? v2 vs Transverse Momentum KIAS Workshop on LHC

20. Recombination Model B. Hong, C.-R. Ji, and D.-P. Min, Phys. Rev. C 73, 054901 (2006) KIAS Workshop on LHC

21. Summary of Present RHIC Results • RHIC collisions produce more particles and energy than ever produced. • Fireball is close to the condition for early universe in energy density estimate and antiproton/proton ratio (> 0.6). • Jet quenching is observed with high ptsingle hadrons and jet correlations → rapid formation of QGP • Hot and dense matter behaves collectively and consistent with the quark recombination model → formation of the strongly interacting liquidlike QGP with the viscosity near zero • Spectra for electron and muons, and their implications for charm production. KIAS Workshop on LHC

22. RHIC Future of HI research • Establish that the QGP is formed via leptons. • Explore the energy and system size dependence for the threshold effect. • Spin structure function of partons, especially gluons by polarized proton collisions • Future Project • LHC heavy-ion collision (CMS in particular) • CBM/SIS200/GSI heavy-ion collisions for the highest baryon density nuclear matter KIAS Workshop on LHC

23. What is LHC? • Run p-p collisions from 2007 - Find Higgs and Supersymmetry, etc. • Run Pb-Pb and other ion collisions from about 2008 -Find QGP and study the detailed properties. KIAS Workshop on LHC

24. Cosmic Timeline Taken from Scientific American (May 06) KIAS Workshop on LHC

25. CMS (Compact Muon Solenoid) KIAS Workshop on LHC

26. Impact parameter resolution • z • r (cm) |η| < 0.7 pT/pT(%) pT (GeV) pT > 3GeV pT > 1GeV Efficiency (%) Efficiency (%) Fakes Fakes dN/dy pT (GeV) Tracking with heavy-ion events KIAS Workshop on LHC

27. Forward Detectors Hermetic calorimetry up to |h|<7 plus zero degree neutral energy. T1 and T2 are multiplicity detectors. Physics: Centrality, Low-x, Limiting fragmentation, strangelets, DCC, etc. ZDC @ 140 m CASTOR Lumi monitor KIAS Workshop on LHC

28. z ETfor 3<||<5 y x Collision Geometry ET(GeV) Assume  = 0.1 radians b (fm) KIAS Workshop on LHC

29. ? Expected Nch KIAS Workshop on LHC

30. by Z0  PHENIX J/ψ BRAHMS Kinematic Range by LHC LHC ε ~ 50 GeV/fm3 Low x High M High Pt Jets Quarkonia Photons Z0, etc. KIAS Workshop on LHC

31.  J/ψ Abundant Quarkonia Large production cross section → should be enough to observe different melting points of 3  states. KIAS Workshop on LHC

32. Ref) H. Satz, hep-ph/0512217 smaller larger Quarkonia and QGP KIAS Workshop on LHC

33. Quarkonia in CMS σM = 50 MeV J/  family • - - • + + Expect ~24k J/ψ and ~ 18/5/3 k ,’,’’ for one month with L=1027cm-2s-1 and 50% efficiency Coverage in central rapidity region KIAS Workshop on LHC

34. Abundant Jet • Large jet cross section • Full jet reconstruction: jet-jet, jet-, jet-Z0correlations • Study in medium modifications KIAS Workshop on LHC

35. axis pT jet Fragmentation of 100 GeV Jets pT relative to thrust axis Precision tracking out to high momenta will give detailed information on modification of the jet by the medium Momentum fraction z along thrust axis KIAS Workshop on LHC

36. Korea in CMS Total Area of Endcap RPC ~1,400 m2 Forward Region of CMS Italy Korea KIAS Workshop on LHC

37. Resistive Plate Chamber Final Gas mixture used in all tests 95.5% Freon 3.5% Isobutane 0.3% SF6 + RH 50% Gap Mechanics KIAS Workshop on LHC

38. History of the Korean RPC • Fundamental studies to develop the Endcap RPCs (1997 - ) • 1) CERN beam test by using high intensity muon beam and 20 Ci 137Cs • 2) Cosmic muon tests (Korea Univ.) • 3) Study of RPC pulses and simulations • 4) Long term aging study for linseed oiled RPC • Design of double gap RPCs for the Endcap Region (2000 – 2003) • 1) Chamber designs • 2) Services for HV, LV, gas, electronics on the chamber level • Detector manufacturing facilities (2000 – 2003) • 1) Gap and chamber production facilities • 2) Gaps and chamber testing facilities for the quality controls • Mass production of the Endcap RPC (2004 - ) KIAS Workshop on LHC

39. Endcap RPC 1. Function : L1 muon triggers 2 wings (RE+, RE-) 4 stations (RE1, RE2, RE3, RE4) Pseudo rapidity covering: 0.9 <η< 2.1(1.6) ηsegmentations : 10 (6) 2. Total # of RPCs :756 (432) Total # of FEBs : 2,268 (1,296) Total # of channels : 85,248 (41,472) 3. By September 2006, the gap production in 0.9 <η < 1.6 will be completed for the first operation of the CMS detector. KIAS Workshop on LHC

40. Korean Endcap RPC Summary of the Performance KIAS Workshop on LHC

41. 1st RE1/2 installed on CMS 18 RE1/2s have been installed on CMS in last 2 weeks ARE1/2 is mated to CSC before installation Installation of the very 1st RE1/2+CSC module CSC RE1/2 KIAS Workshop on LHC

42. KIAS Workshop on LHC

43. CMS 참여를 결정한 순서 Participation of the Korean Heavy-Ion Group in CMS • Korea University (B. Hong and K.S. Sim) • Important role in the endcap RPC production since 1997 • Preparing the computing facility for MC simulation and data analysis • Konkuk University (J.T. Rhee) • Important role in the endcap RPC production since 1997 • City University of Seoul (I.C. Park) • Will use existing computing facility for MC simulation and data analysis • Pusan National University (I.K. Yoo) • Yonsei University (J.H. Kang) • All major HI institutions in Korea will participate in the CMS Heavy-Ion program. KIAS Workshop on LHC

44. Conclusions • RHIC has produced a lot of exciting new results on the quark-gluon matter in extreme conditions. • We look forward to seeing even more exciting results in heavy-ion collisions at LHC. • New energy frontier: √s ~1.2 PeV for a Pb-Pb collision event • Korean Heavy-Ion group has contributed a lot already on the construction of the CMS endcap RPC system. • Korean Heavy-Ion group is preparing the computing farm for the CMS MC generation and data analysis. • All major institutions will participate in the CMS heavy-ion program. KIAS Workshop on LHC