YSchutz_PPTWin

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YSchutz_PPTWin

  1. 1. Heavy-Ion Physics @ LHC <ul><li>Program </li></ul><ul><li>Detectors </li></ul><ul><li>Observables </li></ul><ul><li>~1100 participants: </li></ul><ul><li>26 experimental contributions QM04 </li></ul><ul><ul><li>6 oral : P. Glaessel, V. Manzari, A. Vestbo, H. Takai, B. Wyslouch, S. Blyth. </li></ul></ul><ul><ul><li>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. </li></ul></ul>ATLAS 25 CMS 60 ALICE 1000
  2. 2. The LHC facility <ul><li>Running conditions: </li></ul><ul><li>+ other collision systems: pA, lighter ions (Sn, Kr, Ar, O) & energies (pp @ 5.5 TeV) . </li></ul>April 2007 End 2007 Early 2008 *L max (ALICE) = 10 31 ** L int (ALICE) ~ 0.7 nb -1 /year Collision system PbPb pp <L>/L 0 (%) 10 7 Run time (s/year)  geom (b) L 0 (cm -2 s -1 ) √ s NN (TeV) 0.07 10 34 * 14.0 70-50 10 6 * * 7.7 10 27 5.5
  3. 3. Novel aspects : <ul><li>Probe initial partonic state in a novel Bjorken-x range ( 10 -3 -10 -5 ): </li></ul><ul><ul><li>nuclear shadowing, </li></ul></ul><ul><ul><li>high-density saturated gluon distribution. </li></ul></ul><ul><li>Larger saturation scale ( Q S =0.2A 1/6 √s  = 2.7 GeV ) : particle production dominated by the staturation region. </li></ul>Qualitatively new regime ALICE PPR CERN/LHCC 2003-049 J/ ψ 10 -6 10 -4 10 -2 10 0 x 10 8 10 6 10 4 10 2 10 0 M 2 (GeV 2 ) 10 GeV
  4. 4. Novel aspects : <ul><li>Hard processes contribute significantly to the total AA cross-section ( σ hard / σ tot = 98% ): </li></ul><ul><ul><li>Bulk properties dominated by hard processes; </li></ul></ul><ul><ul><li>Very hard probes are abundantly produced. </li></ul></ul><ul><li>Weakly interacting probes become accessible (  , Z 0 , W ± ). </li></ul>Qualitatively new regime LHC RHIC SPS (h + +h - )/2  0 17 GeV 200 GeV 5500 GeV = √ s LO p+p y=0
  5. 5. 3 experiments JURA ALPES
  6. 6. <ul><li>Which particle multiplicity to expect at LHC ? </li></ul><ul><li>ALICE optimized for dN ch /dY = 4000 , checked up to 8000 (reality factor 2). </li></ul><ul><li>CMS & ATLAS (checked up to 7000 ) will provide good performances over the expected range. </li></ul>HI experiments dN ch /d  ~ 1500 dN ch /d  ~ 2500 hep-ph0104010 5 √ s (GeV) 10 10 2 10 3 10 2 10 3 10 4 1.0 5.0 10.0 15.0 N ch /(0.5N part ) dN ch /d  |  <1 2 5 10 3
  7. 7. ALICE: the dedicated HI experiment <ul><li>Central tracking system: </li></ul><ul><ul><li>ITS </li></ul></ul><ul><ul><li>TPC </li></ul></ul><ul><ul><li>TRD </li></ul></ul><ul><ul><li>TOF </li></ul></ul><ul><li>MUON Spectrometer: </li></ul><ul><ul><li>absorbers </li></ul></ul><ul><ul><li>tracking stations </li></ul></ul><ul><ul><li>trigger chambers </li></ul></ul><ul><ul><li>dipole </li></ul></ul><ul><li>Specialized detectors: </li></ul><ul><ul><li>HMPID </li></ul></ul><ul><ul><li>PHOS </li></ul></ul><ul><li>Forward detectors: </li></ul><ul><ul><li>PMD </li></ul></ul><ul><ul><li>FMD, T0, V0, ZDC </li></ul></ul>Cosmic rays trigger Solenoid magnet 0.5 T
  8. 8. US EMCaL (under discussion) Pb/Sci EMCal  x  = 1.4 x 2  /3 TPC TRD TOF PHOS RICH ITS
  9. 9. ALICE: the dedicated HI experiment <ul><li>Measure flavor content and phase-space distribution event-by-event: </li></ul><ul><ul><li>Most (2  * 1.8 units  ) of the hadrons (dE/dx + ToF) , leptons (dE/dx, transition radiation, magnetic analysis) and photons (high resolution EM calorimetry) ; </li></ul></ul><ul><ul><li>Track and identify from very low (< 100 MeV/c; soft processes) up to very high p t (~100 GeV/c; hard processes) ; </li></ul></ul><ul><ul><li>Identify short lived particles (hyperons, D/B meson) through secondary vertex detection; </li></ul></ul><ul><ul><li>Jet identification; </li></ul></ul>
  10. 10. ALICE PID performances ALICE PPR CERN/LHCC 2003-049
  11. 11. ALICE tracking efficiency  p/p < 1% 100% p t (GeV/c) 1 3 5 0 0.4 0.8 1.2  ALICE PPR CERN/LHCC 2003-049 TPC only
  12. 12. ALICE track resolution at high p t 10 100 p t (GeV/c) 50  p/p (%) 10 30 50  ALICE PPR CERN/LHCC 2003-049
  13. 13. ALICE construction status
  14. 14. ALICE TPC
  15. 15. ALICE Space Frame
  16. 16. ALICE Dipole coil
  17. 17. ALICE pixel 40K channels 200+150  m
  18. 18. CMS <ul><li>Central tracker </li></ul><ul><li>High resolution EM calorimeter </li></ul><ul><li>Hadronic calorimeter </li></ul>Superconducting solenoid magnet 4T <ul><li>Muon spectrometer </li></ul><ul><li>Very forward calorimeters </li></ul><ul><ul><li>ZDC </li></ul></ul><ul><ul><li>CASTOR </li></ul></ul><ul><ul><li>TOTEM </li></ul></ul>
  19. 19. ATLAS Inner detector Solenoid 2T EM calorimeter H calorimeter  detectors
  20. 20. CMS & ATLAS <ul><li>Experiments designed for high p t physics in pp collisions: </li></ul><ul><ul><li>Precise tracking systems in a large solenoid magnetic field; </li></ul></ul><ul><ul><li>Hermetic calorimeters (EM+Hadronic) systems with fine grain segmentation; </li></ul></ul><ul><ul><li>Large acceptance muon spectrometers; </li></ul></ul><ul><ul><li>Accurate measurement of high energy leptons, photons and hadronic jets. </li></ul></ul><ul><li>Provide adequate performances for selected high p t (> 1 GeV/c) probes for HI physics. </li></ul>
  21. 21. 3 Experiments Bulk properties Hard processes Modified by the medium ALICE CMS&ATLAS PID T=  QCD Q s 0 1 2 10 100 p t (GeV/c)
  22. 22. QGP probes: hard processes modified by the medium <ul><li>Q »  QCD , T, Q s   ,  r ~ 1/Q </li></ul><ul><li>Jet quenching: </li></ul><ul><ul><li>Energy degradation of leading hadrons, p t dependence; </li></ul></ul><ul><ul><li>Modification of genuine jet observables; </li></ul></ul><ul><ul><li>Mass dependence of energy loss (light and heavy quarks). </li></ul></ul><ul><li>Dissolution of c’onium & b’onium bound states. </li></ul>
  23. 23. Leading hadron quenching <ul><li>Nuclear modification factor pattern very different at LHC: </li></ul><ul><ul><li>Final state interactions (radiative & collisional energy loss) dominate over nuclear effects (shadowing+Cronin) . </li></ul></ul><ul><li>Measurement of suppression pattern of leading partons remains experimentally the most straightforward observable for jet-tomography analysis. </li></ul>0 20 40 60 80 100 p t (GeV) 0.05 0.1 0.5 1 R AA A+A √s NN = 200, 5500 GeV Vitev&Gyulassy QM02
  24. 24. Jets reconstruction <ul><li>Jets are produced copiously. </li></ul><ul><li>Jets are distinguishable from the HI underlying event. </li></ul>p t (GeV) 2 20 100 200 100/event 1/event 100K/year 100 GeV jet + HI event
  25. 25. Performance by ATLAS Cone algorithm R=0.4 E t > 30 GeV 50 150 250 350 0 40 80 % Efficiency Fake jets E t 50 150 250 350 E t 0 20 10 Energy resolution PbPb pp  E/E (%)
  26. 26. Performance by CMS Cone algorithm R=0.5 E t > 30 GeV Energy resolution E t 50 150 250 350 0 40 80 % E t 0 20 10  E/E (%) 200 300 0 100 0
  27. 27. Jet quenching <ul><li>Excellent jet reconstruction… but challenging to measure medium modification of its shape… </li></ul><ul><li>E t =100 GeV (reduced average jet energy fraction inside R) : </li></ul><ul><ul><li>Radiated energy ~20% </li></ul></ul><ul><ul><li>R=0.3  E/E=3% </li></ul></ul><ul><ul><li>E t UE ~ 100 GeV </li></ul></ul>Medium induced redistribution of jet energy occurs inside cone. C.A. Salgado, U.A. Wiedemann hep-ph/0310079 R vacuum medium E t = 50 GeV E t = 100 GeV 0.2 0 0 0.4 0.6 0.8 1 0.2 R=√(  2 +  2 ) 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1  (R)
  28. 28. Exclusive jets: Redistribution of jet energy <ul><ul><li>Jet shape: distance R to leading particle; </li></ul></ul><ul><ul><li>p T of particles for R < R max ; </li></ul></ul><ul><ul><li>Multiplicity of particles for R < R max ; </li></ul></ul><ul><ul><li>Heating : k T = p  sin(  (particle, jet axis)) ; </li></ul></ul><ul><ul><li>Forward backward correlation  (particle, jet axis); </li></ul></ul><ul><ul><li>Fragmentation function: F(z)=1/N j  dN ch /dz z=p t / p jet . </li></ul></ul>Requires high quality tracking down to low p t .
  29. 29. Fragmentation functions z=p t / p jet p jet 0 0.5 1 z 10 -4 10 -2 1 vacuum medium 0 0.5 1 z 1/N jets dN c /dz 10 -1 10 10 3 reconstructed input p jet z k t
  30. 30. Exclusive jets: Tagging <ul><li>Direct measurement of jet energy:  ,  *, Z 0 </li></ul>40 500 Z 0 (  μ + μ - )-jet 50 10 4  *(  μ + μ - )- jet 50 10 6  -jet p t (GeV) Statistics (evts/month) Channel 50 600 100 6  10 3
  31. 31. Exclusive jets: Tagging <ul><li>Direct measure of jet energy:  ,  *, </li></ul>Z 0 Low (< 10%) background as compared to  /  0
  32. 32. Heavy flavor quenching observables <ul><li>Inclusive: </li></ul><ul><ul><li>Suppression of dilepton invariant mass spectrum (DD  l + l - , BB  l + l - , B  D +  l + )l - </li></ul></ul><ul><ul><li>Suppression of lepton spectra </li></ul></ul><ul><li>Exclusive jet tagging: </li></ul><ul><ul><li>High- p T lepton ( B->Dl  ) & displaced vertex </li></ul></ul><ul><ul><li>Hadronic decay (ex. D 0  K -  + ) & displaced vertex </li></ul></ul>
  33. 33. D quenching ( D 0  K -  + ) <ul><li>Reduced </li></ul><ul><li>Ratio D/hadrons (or D/  0 ) enhanced and sensitive to medium properties. </li></ul>nucl-ex/0311004
  34. 34. c/b Quarkonia <ul><li>1 month statistics of PbPb √s NN =5.5 TeV; </li></ul>|  | < 2.4 2.5 <  < 4 Events/100 MeV 10 3 J/  Y 5 10 15 10 2 dN/d  =8000 M  +  - (GeV) Events/25 MeV 10 4 J/  Y 2 3 4 9 10 11 0 10 5 10 4 dN/d  =5000
  35. 35. Looking forward <ul><li>For a timely completion of LHC and experiments construction in April 2007; </li></ul><ul><ul><li>Accelerators and experiments are today in the production phase. </li></ul></ul><ul><li>For an exciting decade of novel HI physics in continuation of the SPS and complementary to RHIC; </li></ul><ul><ul><li>Detailed physics program, complementary between 1+2 experiments, takes shape (see PPRs, Yellow reports…). </li></ul></ul><ul><li>The 2004 challenge: demonstrate world-wide distributed Monte-Carlo production and data analysis. </li></ul>
  36. 36. Backup
  37. 37. The LHC facility
  38. 38. The LHC facility: average L Time (h) 1 2 3 Experiments  * = 2 - 0.5 m I O = 10 8 ions/bunch 70% 55% 50% Tuning time 0.2 0.4 0.6 0.8 1 < L >/ L 0 0 5 10 15 20 0 ALICE PPR CERN/LHCC 2003-049
  39. 39. Novel aspects : Quantitatively new regime few 10 4 20-30 2-4 5 1.9 0.2 850 200 RHIC few 10 3 V f (fm 3 ) ~10  f (fm/c) ≤ 2  QGP (fm/c) 3  (GeV/fm 3 ) 1.1 T/T c 1  0 QGP (fm/c) 500 dN ch /dy 17 √ s NN (GeV) LHC SPS few 10 5 bigger 5500 X 28 1500-8000 ? 0.1 faster 3.0-4.2 hotter 15-60 denser 30-40 ≥ 10 longer
  40. 40. Novel aspects : <ul><li>Thermodynamics of the QGP phase  Thermodynamics of massless 3-flavor QCD. </li></ul><ul><li>Parton dynamics (  QGP /  0 >50-100 ) dominate the fireball expansion and the collective features of the hadronic final state. </li></ul>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)  s (T)=4  /(18log(5T/Tc))
  41. 41. Scientific objectives of HI physics <ul><li>Study the QCD phase transition and the physics of the QGP state: </li></ul><ul><ul><li>How to apply and extend the SM to a complex and dynamically evolving system of finite size; </li></ul></ul><ul><ul><li>Understand how collective phenomena and macroscopic properties emerge from the microscopic laws of elementary particle physics; </li></ul></ul><ul><ul><li>Answer these questions in the sector of strong interaction by studying matter under conditions of extreme temperature and density. </li></ul></ul>RHIC + CBM LHC
  42. 42. Heavy-ion running scenario <ul><li>Year 1 </li></ul><ul><ul><li>pp: detector commissioning & physics data </li></ul></ul><ul><ul><li>PbPb physics pilot run: global event-properties, observables with large cross-section </li></ul></ul><ul><li>Year 2 (in addition to pp @ 14 TeV, L< 5.10 30 cm -2 s -1 ) </li></ul><ul><ul><li>PbPb @ L~ 10 27 cm -2 s -1 : rare observables </li></ul></ul><ul><li>Year 3 </li></ul><ul><ul><li>p(d,  )Pb @ L~ 10 29 cm -2 s -1 : Nuclear modification of structure function </li></ul></ul><ul><li>Year 4 (as year 2) : L int = 0.5-0.7 nb -1 /year </li></ul><ul><li>Year 5 </li></ul><ul><ul><li>ArAr @ L~ 10 27 -10 29 cm -2 s -1 : energy density dependencies </li></ul></ul><ul><li>Options for later </li></ul><ul><ul><li>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), …. </li></ul></ul>
  43. 43. Combined PID Probability to be a pion Probability to be a kaon Probability to be a proton
  44. 44. Inclusive jets by ALICE <ul><li>Original spectrum </li></ul><ul><li>Measured spectrum  E/E = 25% </li></ul><ul><li>Original spectrum for measured energy 90 < E T < 110 GeV </li></ul>R=0.3 p t > 2 GeV
  45. 45. Exclusive jets: Tagged jets p t (GeV) R AA PbPb + 40 GeV  -jet 1 0 10 20 30 40 0 2 3 4 Tagging 0 10 20 30 40 No Tagging
  46. 46. Heavy quarks jets A. Dainese QM04 <ul><li>Initially produced Qs experience the full collision history: </li></ul><ul><ul><li>Short time scale for production:  1/m Q </li></ul></ul><ul><ul><li>Production suppressed at larger times: m Q »T </li></ul></ul><ul><ul><li>Long time scale for decay  decay »  QGP </li></ul></ul><ul><li>The large masses of c and b quarks make them qualitatively different probes (  massless partons) </li></ul><ul><li>Radiative energy loss suppressed as compared to q, g: (1+  0 2 /  2 ) -2 ;  0 =m Q /E Q </li></ul>
  47. 47. D 0  K -  + reconstruction in ALICE
  48. 50. ALICE TPC E E 510 cm E E 88  s Central electrode
  49. 52. D 0  K -  + reconstruction in ALICE A. Dainese QM04 <ul><li>Invariant-mass analysis of fully-reconstructed topologies originating from displaced secondary vertices </li></ul>
  50. 53. Cone angle (°) 0 20 40 0 0.1 0.2 C.A. Salgado, U.A. Wiedemann  E/E

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