1 / 53

Heavy-Ion Physics @ LHC

Heavy-Ion Physics @ LHC. ~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. Program

louis-cruz
Télécharger la présentation

Heavy-Ion Physics @ LHC

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Heavy-Ion Physics @ LHC • ~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 pT 17, 20, 21, Flavor 18, 19, 23, Instr. 1, 2, 7, 8, 10, 12, 14, 15, 16, 17, 22, 30. Program Detectors Observables Yves Schutz

  2. The LHC facility • Running conditions: • + other collision systems: pA, lighter ions (Sn, Kr, Ar, O) & energies (pp @ 5.5 TeV). April 2007 End 2007 Early 2008 *Lmax(ALICE) = 1031 ** Lint(ALICE) ~ 0.7 nb-1/year Yves Schutz

  3. 108 106 104 102 100 M2 (GeV2) 10 GeV 10-6 10-4 10-2 100 x J/ψ Qualitatively new regime Novel aspects: • Probe initial partonic state in a novel Bjorken-x range (10-3-10-5): • nuclear shadowing, • high-density saturated gluon distribution. • Larger saturation scale (QS=0.2A1/6√sd= 2.7 GeV): particle production dominated by the staturation region. ALICE PPR CERN/LHCC 2003-049 Yves Schutz

  4. (h++h-)/2 p0 √s LO p+p y=0 = 5500 GeV 200 GeV 17 GeV LHC RHIC SPS Qualitatively new regime Novel aspects: • Hard processes contribute significantly to the total AA cross-section (σhard/σtot = 98%): • Bulk properties dominated by hard processes; • Very hard probes are abundantly produced. • Weakly interacting probes become accessible (g, Z0, W±). Yves Schutz

  5. 3 experiments JURA ALPES Yves Schutz

  6. 5 15.0 10.0 Nch/(0.5Npart) dNch/dh|h<1 103 5.0 5 1.0 2 10 102 103 102 103 104 √s (GeV) hep-ph0104010 HI experiments • Which particle multiplicity to expect at LHC ? • ALICE optimized for dNch/dY = 4000,checked up to 8000 (reality factor 2). • CMS & ATLAS (checked up to 7000) will provide good performances over the expected range. dNch/dh ~ 2500 dNch/dh ~ 1500 Yves Schutz

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

  8. US EMCaL (under discussion) RICH Pb/Sci EMCal Dh x Df = 1.4 x 2p/3 TPC TRD TOF PHOS ITS Yves Schutz

  9. ALICE: the dedicated HI experiment • Measure flavor content and phase-space distribution event-by-event: • Most (2p * 1.8 units h) 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 pt(~100 GeV/c; hard processes); • Identify short lived particles (hyperons, D/B meson) through secondary vertex detection; • Jet identification; Yves Schutz

  10. ALICE PID performances ALICE PPR CERN/LHCC 2003-049 Yves Schutz

  11. ALICE tracking efficiency ALICE PPR CERN/LHCC 2003-049 e TPC only 1.2 100% 0.8 Dp/p < 1% 0.4 0 1 3 5 pt (GeV/c) Yves Schutz

  12. ALICE track resolution at high pt ALICE PPR CERN/LHCC 2003-049 Dp/p (%) 50 30 9% 10 50 pt (GeV/c) 100 10 Yves Schutz

  13. ALICE construction status Yves Schutz

  14. ALICE TPC Yves Schutz

  15. ALICE Space Frame Yves Schutz

  16. ALICE Dipole coil Yves Schutz

  17. 40K channels 200+150 mm ALICE pixel Yves Schutz

  18. CMS • Very forward calorimeters • ZDC • CASTOR • TOTEM • Central tracker • High resolution EM calorimeter • Hadronic calorimeter Superconducting solenoid magnet 4T • Muon spectrometer Yves Schutz

  19. ATLAS m detectors EM calorimeter Solenoid 2T Inner detector H calorimeter Yves Schutz

  20. CMS & ATLAS • Experiments designed for high pt 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 pt(> 1 GeV/c) probes for HI physics. Yves Schutz

  21. 0 1 2 10 100 pt (GeV/c) 3 Experiments Qs T=LQCD Hard processes Modified by the medium Bulk properties ALICE PID CMS&ATLAS Yves Schutz

  22. QGP probes: hard processes modified by the medium Q » LQCD, T, Qs Dt, Dr ~ 1/Q • Jet quenching: • Energy degradation of leading hadrons, pt dependence; • Modification of genuine jet observables; • Mass dependence of energy loss (light and heavy quarks). • Dissolution of c’onium & b’onium bound states. Yves Schutz

  23. 1 0.5 RAA 0.1 A+A √sNN = 200, 5500 GeV 0.05 0 20 40 60 80 100 pt (GeV) Vitev&Gyulassy QM02 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. Yves Schutz

  24. Jets reconstruction • Jets are produced copiously. • Jets are distinguishable from the HI underlying event. pt (GeV) 20 100 200 2 100/event 1/event 100K/year + HI event 100 GeV jet Yves Schutz

  25. % 80 Efficiency Fake jets 40 0 DE/E (%) 50 150 250 350 Et 20 Energy resolution PbPb 10 pp 0 50 150 250 350 Et Performance by ATLAS Cone algorithm R=0.4 Et > 30 GeV Yves Schutz

  26. % DE/E (%) 80 20 40 10 0 0 50 350 150 250 Et 0 100 300 0 200 Performance by CMS Cone algorithm R=0.5 Et > 30 GeV Energy resolution Et Yves Schutz

  27. vacuum 1 0.8 medium 0.6 0.4 R Et = 50 GeV 0.2 0 r(R) 1 0.8 0.6 0.4 Et = 100 GeV 0.2 0 0 0.8 0.2 0.4 0.6 1 R=√(Dh2+Df2) Jet quenching • Excellent jet reconstruction… but challenging to measure medium modification of its shape… • Et=100 GeV (reduced average jet energy fraction inside R): • Radiated energy ~20% • R=0.3 DE/E=3% • EtUE ~ 100 GeV Medium induced redistribution of jet energy occurs inside cone. C.A. Salgado, U.A. Wiedemann hep-ph/0310079 Yves Schutz

  28. Exclusive jets:Redistribution of jet energy • Jet shape: distance R to leading particle; • pT of particles for R < Rmax; • Multiplicity of particles for R < Rmax ; • Heating: kT = p  sin((particle, jet axis)) ; • Forward backward correlation: (particle, jet axis); • Fragmentation function: F(z)=1/NjdNch/dz z=pt/pjet. Requires high quality tracking down to low pt . Yves Schutz

  29. 1 103 reconstructed input 10-2 1/NjetsdNc/dz 10 vacuum medium z pjet 10-1 10-4 kt 0 0.5 1 z 0 0.5 1 z pjet z=pt/ pjet Fragmentation functions Yves Schutz

  30. Channel Statistics (evts/month) pt (GeV) g-jet 106 50 6103 100 g*(μ+ μ-)- jet 104 50 500 40 Z0 (μ+ μ-)-jet 600 50 Exclusive jets:Tagging • Direct measurement of jet energy: g, g*, Z0 Yves Schutz

  31. Exclusive jets:Tagging Z0 • Direct measure of jet energy: g, g*, Low (< 10%) background as compared to g/p0 Yves Schutz

  32. 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- pT lepton (B→Dl)&displaced vertex • Hadronic decay (ex. D0K-p+) &displaced vertex Yves Schutz

  33. D quenching (D0K-p+) nucl-ex/0311004 • Reduced • Ratio D/hadrons (or D/p0) enhanced and sensitive to medium properties. Yves Schutz

  34. dN/dh=8000 105 J/ dN/dh=5000 Y Y 103 J/ Events/100 MeV Events/25 MeV 104 104 102 5 10 15 0 9 11 2 3 4 10 Mm+m-(GeV) c/b Quarkonia • 1 month statistics of PbPb √sNN=5.5 TeV; |h| < 2.4 2.5<h < 4 Yves Schutz

  35. 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. Yves Schutz

  36. Backup Yves Schutz

  37. The LHC facility Yves Schutz

  38. <L>/L0 1 0.8 0.6 0.4 0.2 0 0 5 10 15 20 ALICE PPR CERN/LHCC 2003-049 The LHC facility: average L b* = 2 - 0.5 m IO = 108 ions/bunch 70% 1 Tuning time 55% Experiments 2 50% 3 Time (h) Yves Schutz

  39. Quantitatively new regime Novel aspects: Yves Schutz

  40. Qualitatively new regime Novel aspects: • Thermodynamics of the QGP phase  Thermodynamics of massless 3-flavor QCD. • Parton dynamics (tQGP/t0>50-100) dominate the fireball expansion and the collective features of the hadronic final state. as(T)=4p/(18log(5T/Tc)) mu= md = ms mu = md mu = md ; ms mu,d HQ suppressed exp(-mc,b,t/T) Yves Schutz

  41. Scientific objectives of HI physics RHIC + CBM • 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. LHC Yves Schutz

  42. 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 pp @ 14 TeV, L< 5.1030cm-2s-1 ) • PbPb @ L~ 1027cm-2s-1: rare observables • Year 3 • p(d, a)Pb @ L~ 1029cm-2s-1 : Nuclear modification of structure function • Year 4 (as year 2) : Lint = 0.5-0.7 nb-1/year • Year 5 • ArAr @ L~ 1027 -1029cm-2s-1 : energy density dependencies • Options for later • pp @ 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), …. Yves Schutz

  43. Combined PID Probability to be a proton Probability to be a pion Probability to be a kaon Yves Schutz

  44. Inclusive jets by ALICE R=0.3 pt > 2 GeV • Original spectrum • Measured spectrum DE/E = 25% • Original spectrum for measured energy 90 < ET < 110 GeV Yves Schutz

  45. 4 3 Tagging No Tagging 2 1 0 0 10 0 10 20 30 40 20 30 40 Exclusive jets:Tagged jets PbPb + 40 GeV g-jet RAA pt (GeV) Yves Schutz

  46. Heavy quarks jets A. Dainese QM04 • Initially produced Qs experience the full collision history: • Short time scale for production: t1/mQ • Production suppressed at larger times: mQ»T • Long time scale for decay tdecay»tQGP • 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+02/2)-2; 0=mQ/EQ Yves Schutz

  47. D0K-p+ reconstruction in ALICE Yves Schutz

  48. Yves Schutz

  49. Yves Schutz

  50. ALICE TPC E E E E 88ms 510 cm Central electrode Yves Schutz

More Related