QM2004Yves Schutz 1 Heavy-Ion LHC  Program  Detectors  Observables   ~1100 participants:  26 experimental contributions QM04  6 oral: P. Glaessel, V. Manzari, A. Vestbo, H. Takai, B. Wyslouch, S. Blyth.  20 posters: Spectra 23, HBT 1, High p T 17, 20, 21, Flavor 18, 19, 23, Instr. 1, 2, 7, 8, 10, 12, 14, 15, 16, 17, 22, 30.  1000ALICE  60CMS  25ATLAS

QM2004Yves Schutz2 The LHC facility  Running conditions:  + other collision systems: pA, lighter ions (Sn, Kr, Ar, O) & energies 5.5 TeV). Collision system pp PbPb √s NN (TeV) L 0 (cm -2 s -1 ) /L 0 (%) Run time (s/year)  geom (b) * * * 7.7 April 2007 End 2007 Early 2008 *L max (ALICE) = ** L int (ALICE) ~ 0.7 nb -1 /year

QM2004Yves Schutz3 Novel aspects :  Probe initial partonic state in a novel Bjorken-x range ( ): nuclear shadowing, high-density saturated gluon distribution.  Larger saturation scale (Q S =0.2A 1/6 √s  = 2.7 GeV) : particle production dominated by the staturation region. Qualitatively new regime J/ψ ALICE PPR CERN/LHCC GeV

QM2004Yves Schutz4 Novel aspects : Qualitatively new regime  Hard processes contribute significantly to the total AA cross- section ( σ hard /σ tot = 98% ): Bulk properties dominated by hard processes; Very hard probes are abundantly produced.  Weakly interacting probes become accessible (, Z 0, W ± ).

QM2004Yves Schutz5 3 experiments JURA ALPES

QM2004Yves Schutz6 hep-ph √s (GeV) N ch /(0.5N part ) dN ch /d  |  <  Which particle multiplicity to expect at LHC ?  ALICE optimized for dN ch /dY = 4000, checked up to 8000 (reality factor 2).  CMS & ATLAS (checked up to 7000) will provide good performances over the expected range. dN ch /d  ~ 1500 HI experiments dN ch /d  ~ 2500

QM2004Yves Schutz7 ALICE: the dedicated HI experiment Solenoid magnet 0.5 T Central tracking system: ITS TPC TRD TOF MUON Spectrometer: absorbers tracking stations trigger chambers dipole Specialized detectors: HMPID PHOS Forward detectors: PMD FMD, T0, V0, ZDC Cosmic rays trigger

QM2004Yves Schutz8 Pb/Sci EMCal  x  = 1.4 x 2  /3 TPC TRD TOF PHOS RICH ITS US EMCaL (under discussion)

QM2004Yves Schutz9 ALICE: the dedicated HI experiment  Measure flavor content and phase-space distribution event-by-event: Most (2 * 1.8 units ) of the hadrons (dE/dx + ToF), leptons (dE/dx, transition radiation, magnetic analysis) and photons (high resolution EM calorimetry); Track and identify from very low (< 100 MeV/c; soft processes) up to very high p t (~100 GeV/c; hard processes) ; Identify short lived particles (hyperons, D/B meson) through secondary vertex detection; Jet identification;

QM2004Yves Schutz10 ALICE PID performances ALICE PPR CERN/LHCC

QM2004Yves Schutz11 ALICE tracking efficiency  p/p < 1% 100% p t (GeV/c)  ALICE PPR CERN/LHCC TPC only

QM2004Yves Schutz12 ALICE track resolution at high p t p t (GeV/c)50  p/p (%)  ALICE PPR CERN/LHCC

QM2004Yves Schutz13 ALICE construction status

QM2004Yves Schutz14 ALICE TPC

QM2004Yves Schutz15 ALICE Space Frame

QM2004Yves Schutz16 ALICE Dipole coil

QM2004Yves Schutz17 ALICE pixel 40K channels  m

QM2004Yves Schutz18 CMS Central tracker High resolution EM calorimeter Hadronic calorimeter Superconducting solenoid magnet 4T Muon spectrometer Very forward calorimeters ZDC CASTOR TOTEM

QM2004Yves Schutz19 ATLAS Inner detector Solenoid 2T EM calorimeter H calorimeter  detectors

QM2004Yves Schutz20 CMS & ATLAS  Experiments designed for high p t physics in pp collisions: Precise tracking systems in a large solenoid magnetic field; Hermetic calorimeters (EM+Hadronic) systems with fine grain segmentation; Large acceptance muon spectrometers; Accurate measurement of high energy leptons, photons and hadronic jets.  Provide adequate performances for selected high p t (> 1 GeV/c) probes for HI physics.

QM2004Yves Schutz p t (GeV/c) Bulk properties Hard processes Modified by the medium ALICE CMS&ATLAS 3 Experiments PID T=  QCD QsQs

QM2004Yves Schutz22 QGP probes: hard processes modified by the medium Q »  QCD, T, Q s  , r ~ 1/Q  Jet quenching: Energy degradation of leading hadrons, p t dependence; Modification of genuine jet observables; Mass dependence of energy loss (light and heavy quarks).  Dissolution of c’onium & b’onium bound states.

QM2004Yves Schutz23 Leading hadron quenching  Nuclear modification factor pattern very different at LHC: Final state interactions (radiative & collisional energy loss) dominate over nuclear effects (shadowing+Cronin).  Measurement of suppression pattern of leading partons remains experimentally the most straightforward observable for jet-tomography analysis p t (GeV) R AA A+A √s NN = 200, 5500 GeV Vitev&Gyulassy QM02

QM2004Yves Schutz24 Jets reconstruction  Jets are produced copiously.  Jets are distinguishable from the HI underlying event. p t (GeV) /event1/event100K/year 100 GeV jet + HI event

QM2004Yves Schutz25 Performance by ATLAS % Efficiency Fake jets EtEt Cone algorithm R=0.4 E t > 30 GeV EtEt Energy resolution PbPb pp  E/E (%)

QM2004Yves Schutz % EtEt  E/E (%) Performance by CMS Cone algorithm R=0.5 E t > 30 GeV Energy resolution EtEt

QM2004Yves Schutz27 Jet quenching  Excellent jet reconstruction… but challenging to measure medium modification of its shape…  E t =100 GeV (reduced average jet energy fraction inside R) : Radiated energy ~20% R=0.3 E/E=3% E t UE ~ 100 GeV R Medium induced redistribution of jet energy occurs inside cone. C.A. Salgado, U.A. Wiedemann hep-ph/

QM2004Yves Schutz28 Exclusive jets: Redistribution of jet energy Jet shape: distance R to leading particle; p T of particles for R < R max ; Multiplicity of particles for R < R max ; Heating: k T = p  sin((particle, jet axis)) ; Forward backward correlation(particle, jet axis); Fragmentation function: F(z)=1/N j dN ch /dz z=p t / p jet. Requires high quality tracking down to low p t.

QM2004Yves Schutz29 Fragmentation functions z vacuum medium z 1/N jets dN c /dz reconstructed input p jet z ktkt z=p t /p jet

QM2004Yves Schutz30 Exclusive jets: Tagging  Direct measurement of jet energy: , *, Z Z 0 (μ + μ - )-jet *(μ + μ - )- jet -jet p t (GeV) Statistics (evts/month) Channel 10 3

QM2004Yves Schutz31 Exclusive jets: Tagging  Direct measure of jet energy: , *, Z0Z0 Low (< 10%) background as compared to / 0

QM2004Yves Schutz32 Heavy flavor quenching observables  Inclusive: Suppression of dilepton invariant mass spectrum (DDl + l -, BB l + l -, B D + l + )l - Suppression of lepton spectra  Exclusive jet tagging: High- p T lepton (B → Dl) & displaced vertex Hadronic decay (ex. D 0 K -  + ) & displaced vertex

QM2004Yves Schutz33 D quenching (D 0 K -  + )  Reduced  Ratio D/hadrons (or D/ 0 ) enhanced and sensitive to medium properties. nucl-ex/

QM2004Yves Schutz34 c/b Quarkonia  1 month statistics of PbPb √s NN =5.5 TeV; Events/100 MeV 10 3 J/  Y dN/d=8000 M  +  - (GeV) Events/25 MeV 10 4 J/  Y dN/d=5000 |  | < <  < 4

QM2004Yves Schutz35 Looking forward  For a timely completion of LHC and experiments construction in April 2007; Accelerators and experiments are today in the production phase.  For an exciting decade of novel HI physics in continuation of the SPS and complementary to RHIC; Detailed physics program, complementary between 1+2 experiments, takes shape (see PPRs, Yellow reports…).  The 2004 challenge: demonstrate world- wide distributed Monte-Carlo production and data analysis.

QM2004Yves Schutz 36 Backup

QM2004Yves Schutz37 The LHC facility

QM2004Yves Schutz38 Time (h) The LHC facility: average L Experiments  * = m I O = 10 8 ions/bunch 70% 55% 50% Tuning time / L ALICE PPR CERN/LHCC

QM2004Yves Schutz39 Novel aspects : SPSRHICLHC √s NN (GeV)17200 dN ch /dy  0 QGP (fm/c) 10.2 T/T c  (GeV/fm 3 ) 35  QGP (fm/c) ≤22-4  f (fm/c) ~ V f (fm 3 )few 10 3 few 10 4 few 10 5 bigger 5500X ? 0.1faster hotter 15-60denser ≥10 longer Quantitatively new regime

QM2004Yves Schutz40 Novel aspects : Qualitatively new regime m u = m d = m s m u = m d m u = m d ; m s  m u,d HQ suppressed exp(-m c,b,t /T)  Thermodynamics of the QGP phase  Thermodynamics of massless 3-flavor QCD.  Parton dynamics ( QGP /  0 > ) dominate the fireball expansion and the collective features of the hadronic final state.  s (T)=4  /(18log(5T/Tc))

QM2004Yves Schutz41 Scientific objectives of HI physics  Study the QCD phase transition and the physics of the QGP state: How to apply and extend the SM to a complex and dynamically evolving system of finite size; Understand how collective phenomena and macroscopic properties emerge from the microscopic laws of elementary particle physics; Answer these questions in the sector of strong interaction by studying matter under conditions of extreme temperature and density. RHIC + CBM LHC

QM2004Yves Schutz42 Heavy-ion running scenario  Year 1 pp: detector commissioning & physics data PbPb physics pilot run: global event-properties, observables with large cross-section  Year 2 (in addition to 14 TeV, L< cm -2 s -1 ) L~ cm -2 s -1 : rare observables  Year 3 p(d, L~ cm -2 s -1 : Nuclear modification of structure function  Year 4 (as year 2) : L int = nb -1 /year  Year 5 L~ cm -2 s -1 : energy density dependencies  Options for later 5.5 TeV, pA (A scan to map A dependence), AA (A scan to map energy-density dependence), PbPb (energy- excitation function down towards RHIC), ….

QM2004Yves Schutz43 Combined PID Probability to be a pion Probability to be a kaon Probability to be a proton

QM2004Yves Schutz44 Inclusive jets by ALICE ● Original spectrum ● Measured spectrum  E/E = 25% ● Original spectrum for measured energy 90 < E T < 110 GeV R=0.3 p t > 2 GeV

QM2004Yves Schutz45 Exclusive jets: Tagged jets p t (GeV) R AA PbPb + 40 GeV  -jet Tagging No Tagging

QM2004Yves Schutz46 Heavy quarks jets A. Dainese QM04  Initially produced Qs experience the full collision history: Short time scale for production: 1/m Q Production suppressed at larger times: m Q »T Long time scale for decay  decay » QGP  The large masses of c and b quarks make them qualitatively different probes ( massless partons)  Radiative energy loss suppressed as compared to q, g: (1+ 0 2 / 2 ) -2 ;  0 =m Q /E Q

QM2004Yves Schutz47 D 0 K -  + reconstruction in ALICE

QM2004Yves Schutz48

QM2004Yves Schutz49

QM2004Yves Schutz50 ALICE TPC E E 510 cm E E 88  s Central electrode

QM2004Yves Schutz51

QM2004Yves Schutz52 D 0 K -  + reconstruction in ALICE A. Dainese QM04  Invariant-mass analysis of fully- reconstructed topologies originating from displaced secondary vertices

QM2004Yves Schutz53