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The h eavy i on c ollider e xperiment @ LHC A L I C E

The h eavy i on c ollider e xperiment @ LHC A L I C E. Ginés MARTINEZ # for the ALICE Collaboration. # Photon Group @ S UBATECH(IN2P3/CNRS – ENM - UN) Nantes, France. Outlook. Why a Heavy Ion Experiment @ LHC? Goals Building ALICE. The study of the Quark Gluon Plasma. Krasch QM2001.

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The h eavy i on c ollider e xperiment @ LHC A L I C E

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  1. The heavy ion collider experiment @ LHCA L I C E Ginés MARTINEZ# for the ALICE Collaboration #Photon Group @ SUBATECH(IN2P3/CNRS – ENM - UN) Nantes, France Rencontres de Moriond March 17-24 2001

  2. Outlook • Why a Heavy Ion Experiment @ LHC? • Goals • Building ALICE Rencontres de Moriond March 17-24 2001

  3. The study of the Quark Gluon Plasma Krasch QM2001 Lattice QCD calculations nf=2 Tc = 173±8±SysErr MeV nf=3 Tc = 153±8±SysErr MeV ec= 700 ± 300 MeV • QCD-thermodynamics • Properties of the QGP and of the phase transition: • Chiral transition • Deconfinement Rencontres de Moriond March 17-24 2001

  4. Towards QCD thermodynamics The TOOLS: Heavy Ion Collisions: SPS => RHIC => LHC The relation with QCD at finite temperature • The pp & pA baseline • Equilibration • Probes of QGP formation? • QGP Initial conditions? Collision dynamics Rencontres de Moriond March 17-24 2001

  5. collision dynamics p+p and p+A baseline ! Sensitivity to late stages in HI collisions! Final state probes Penetrating probes The QGP phase Rencontres de Moriond March 17-24 2001

  6. Why HI program @ LHC? @ LHC : Hotter – bigger - longer J. Schukraft QM2001 Rencontres de Moriond March 17-24 2001

  7. The gluon-gluon physics… • Gluon distribution in nuclei grows for small values of x = 2pT /s1/2and high gluon densities are reached . • For high densities (rT >> L2QCD) in large nuclei & small x, the gluon distribution can be computed in the weak coupling method. • The classical color field. • A large number of gluons are freed in the early stage of the collision => Equilibration PRD10(74)1649, PRC49(94)2233, PRD49(94)3352, PRD53(96)458, PRC56(97)2219 Rencontres de Moriond March 17-24 2001

  8. Advantages of Pb+Pb collisions @ LHC • Better connection with QCD theory (via the asymptotically free field theory) A E • Initial gluon multiplicity (R.Venugopalan QM01, PRL86(01)1717) • Initial equilibration conditions (D. Son QM01,hep-ph/0009237) • Longer lifetime of the plasma • Ideal plasma : e/ec ~ 5 : higher T • Zero baryon density (already p/p ~ 0.6 @ RHIC) • New probes : Jets, Open charm & beauty, bottonium Rencontres de Moriond March 17-24 2001

  9. Forward energy dN/dy hadron pT distribution Particle ratios Strange particles Multiplicity Energy Density HBT and dynamical evolution Freeze-out temperature Fluctuations Collective motion Final state probes • 12200 p’s • 1700 K’s • 700 h’s • 570 p, n, p, n ‘s • …. -1<h<1 Pb+Pb @ 5.5A TeV Rencontres de Moriond March 17-24 2001

  10. Real and virtual photons Quarkonia: J/Y & Y Open Charm & Beauty Light vector mesons Jets Initial stage Thermal radiation: Tini Colour screening of heavy quarks Jet-matter interaction Chiral transition Penetrating probes Rencontres de Moriond March 17-24 2001

  11. Jet Matter interaction 1-3 GeV/fm# Large production of jets @ LHC energies 1 jet/GeV/s in the ALICE acceptance at ET =50 GeV Dt0 B A Looking for Jet matter interaction: • High pT particle distributions • Identification of jets … • Tagging with photons: • High pT particles • Jets g #Interference with vacuum and LPM, Jet enhancement Ejet dependence of DE pT> 10 – 20 GeV Urs. Wiedemann QM2001 et NPB588(00)203 Rencontres de Moriond March 17-24 2001

  12. Event Characterisation dNch/dy pT distribution Particle ratios Strange baryons Fluctuations Light vector mesons Quarkonium Open charm & beauty Photon & Dilepton Jet quenching … Building ALICE Rencontres de Moriond March 17-24 2001

  13. dNch/dhDh=1~ 8000 Tracking efficiency ~90% 2 tracks eff. 80% Dp>15 MeV/c • Time Projection Chamber: Main tracking detector of ALICE central barrel • Inner radius: Track separation • Rin = 0.8 m • Outer radius: dE/dx & p resolution# Rout= 2.5 m • Large acceptance Dh <0.9 • 200Hz rate capability • MWPC read-out 32 m2, 40% Oc • 5 105 pads x 500 time bins • 60 Mbyte/evt => DC, RoI, L3 … 5 m TPC Ne+CO2(10%) • PID below ~600 MeV/c • Low Dp tracks #Magnetic field of the L3 magnet 0.4T 5% @ 5 GeV/c Rencontres de Moriond March 17-24 2001

  14. The ALICE PID Time of Flight High Momentum Particle Identification Transition Radiation Detector • 0.5 < p < 5 GeV/c • e, p, K, p ALICE solution ToF prototype Multigap Resistive Plate Chamber • pT distributions • Particles ratios: Tfreeze-out • Fluctuations • Strangeness production • Light vector mesons • Open charm • Jet physics ToF • Large acceptance • MRPC • s= 150 ps • p,K,p • 0.5<p<2.5 GeV/c 10cm Rencontres de Moriond March 17-24 2001

  15. High momentum particles • High Momentum PID: • Hard processes • 1 GeV/c < p < 5 GeV/c • Rich-imaging technique • Small acceptance 7x HMPID Rencontres de Moriond March 17-24 2001

  16. Electron Identificator of ALICE • J/Y in Zero baryon density • Open charm normalization • J/Y source from Open Beauty • D annihilation? • G production • Light vector resonances: f, w • Electron detector • 10-3 pion rejection • Large acceptance • Transition Radiation Detector e channel TRD Pb+Pb central collisions 6x g ~ 103 EX ~ 3-30 KeV Rencontres de Moriond March 17-24 2001

  17. Primary and secondary Vertex Position p L • Secondary vertex from hyperon decays • Open charm & beauty physics • Tracking of low pT particles • Improving momentum resolution • Strangelets W- I T S p- K- ITS • Large acceptance • 15000 tracks • s~100mm in rf • 6 Silicon layers: • 2 Silicon Pixel layers • 2 Silicon Drift layers • 2 Silicon Strip layers D =>Kp 107evt Rencontres de Moriond March 17-24 2001

  18. Photon detection 10 • Thermal radiation • High pt physics • Tagged jets • 1200 g pT>40 GeV/c 5x Thermal/Decay 1 PHOS PHOS Module 5% 0.1 hep-ph/9906325 pT(GeV/c) 1 2 3 4 • EM calorimeter • PbWO4: spectrometer: p0,h • Small acceptance 0.07 DhDf/2p • 1< pT < 5 GeV/c • 5< pT <100 GeV/c Rencontres de Moriond March 17-24 2001

  19. Di muon channel • Quarkonium physics: • J/Y and Y families • ~ 100 MeV 2.4 < h < 4.0 DiMuon • em coin.: • Intermediate • rapidity • DD, BB • production Rencontres de Moriond March 17-24 2001

  20. ALICE = The result of QGP physics requirements at LHC + PMD FMD CASTOR ZDC Trigger DAQ Offline Rencontres de Moriond March 17-24 2001

  21. Running conditions • Pb+Pb @ 5.5A TeV • 106s per year • 8000 Hz (L=1027 cm-2s-1) • Data rate full ALICE 50 Hz (TPC challenge) • pp & pA running • Lighter ions @ higher luminosity. • Beginning 2007 Rencontres de Moriond March 17-24 2001

  22. conclusions • HI in LHC: a rigorous step towards the QGP physics • Perturbative + weak coupling methods • Direct partonic probes: Jets. • The LHC HI dedicated experiment: ALICE • Penetrating and final state probes • 884 members & 28 countries & 77 institutes • Rendez-vous @ CERN March-April 2007 Rencontres de Moriond March 17-24 2001

  23. A new research domain Quark Matter 2002 in Nantes Rencontres de Moriond March 17-24 2001

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