1. Prague, 07.11.2007 Andrea Dainese 1 Heavy Quarks in view of the LHC Andrea Dainese INFN (ALICE Collaboration)

2. Prague, 07.11.2007 Andrea Dainese 2 Layout High-p T (heavy-flavour) particle production in hadronic collisions –from pp to AA– in factorized QCD pp baseline: pQCD calculations nuclear effects, in initial and final state What have we learnt at Tevatron and RHIC? What will be new at the LHC? What do we expect? What should we measure? Experimental Perspectives at the LHC PARTONENERGYLOSS

3. Prague, 07.11.2007 Andrea Dainese 3 Heavy-flavour production: pp proton-proton collisions: factorized pQCD approach  s /2 c c D D x1x1 x2x2 Q2Q2 PDF : Q 2 evolution calculated in pQCD initial condition from data (HERA) FF : non-perturbative phenomenolgy + fit to data (e + e - ) calculable as perturbative series of strong coupling  s (  R )

4. Prague, 07.11.2007 Andrea Dainese 4 pp  QQ: pQCD calculations vs data Calculation of partonic cross section standard: Fixed Order (NLO) Massive (e.g. MNR code) state-of-the-art: Fixed Order Next-to-Leading Log (FONLL)  more accurate at high p T Cacciari, Frixione, Mangano, Nason and Ridolfi, JHEP0407 (2004) 033 B production at Tevatron (1.96 TeV) is well described by FONLL CDF, PRL91 (2003) 241804 FONLL: Cacciari, Nason Charm production slightly underpredicted at Tevatron (1.96 TeV) Cacciari, Nason, Vogt, PRL95 (2005) 122001 & at RHIC (200 GeV) Q  e  +X QM06 update later

5. Prague, 07.11.2007 Andrea Dainese 5 Heavy-flavour production: AA A A Binary scaling for hard yields: Binary scaling is “broken” by: c c D D x f g Pb / f g p LHC RHIC SPS R AA 1 Q 2 = 5 GeV 2 pTpT R AB 1 ~2-4 GeV/c kL  kTkL  kT Cronin enhancement initial-state effects: PDF shadowing k T broadening (‘Cronin’) medium formed in the collision A A c c D D u final-state effects energy loss? [next slide] in-medium hadronization (recombination?) recombination: p H =  p q fragmentation: p H = z p q  baryon/meson enhancement

6. Prague, 07.11.2007 Andrea Dainese 6 Calculating Parton Energy Loss Baier, Dokshitzer, Mueller, Peigne‘, Schiff, NPB 483 (1997) 291. Zakharov, JTEPL 63 (1996) 952. Salgado, Wiedemann, PRD 68(2003) 014008. BDMPS-Z formalism path length L kTkT  Radiated-gluon energy distrib.: transport coefficient sets the scale of the radiated energy related to constraint k T < , controls shape at  <<  c Casimir coupling factor: 4/3 for q, 3 for g (BDMPS case)

7. Prague, 07.11.2007 Andrea Dainese 7 Model vs RHIC “light” data Model: pQCD + E loss probability + detailed collision geometry Density ( ) “tuned” to match R AA in central Au-Au at 200 GeV matches p T -indepence of suppression at high p T Dainese, Loizides, Paic, EPJC 38 (2005) 461. (Quark Matter 05) Same theoretical calculation (SW quenching weights) and similar results in Eskola, Honkanen, Salgado, Wiedemann, NPA747 (2005) 511

8. Prague, 07.11.2007 Andrea Dainese 8 large  R AA indep. of Limited sensitivity of R AA Strong suppression requires very large density Surface emission scenario R AA determined by geometry rather than by density itself  Limited sensitivity to  Need more differential observables: massive partons R AA vs reaction plane study of jet shapes … Eskola, Honkanen, Salgado, Wiedemann, NPA 747 (2005) 511. ?

9. Prague, 07.11.2007 Andrea Dainese 9 Lower E loss for heavy quarks ? In vacuum, gluon radiation suppressed at  < m Q /E Q  “dead cone” effect Dead cone implies lower energy loss (Dokshitzer-Kharzeev, 2001) : energy distribution  d  /d  of radiated gluons suppressed by angle- dependent factor suppress high-  tail Q Dokshitzer, Khoze, Troyan, JPG 17 (1991) 1602. Dokshitzer and Kharzeev, PLB 519 (2001) 199. Dokshitzer Gluonsstrahlung probability R = 10 5 Detailed massive calculation confirms this qualitative feature (Armesto, Salgado, Wiedemann, PRD 69 (2004) 114003)

10. Prague, 07.11.2007 Andrea Dainese 10 Charm R AA at RHIC effect of the mass thermalized component Small effect of mass for charm (~50% for D, ~30% for e) at low p T [large uncertainties!] Basically no effect in “safe” p T -region Armesto, Dainese, Salgado, Wiedemann, PRD 71 (2005) 054027. (extracted from light-flv hadron data) larger uncertainties other contributions become important

11. Prague, 07.11.2007 Andrea Dainese 11 Charm + beauty + DY electrons at RHIC (pQCD baseline revised, and its uncertainties) FONLL calculation: Cacciari, Nason, Vogt, PRL95 (2005) 122001 Drell-Yan from: Gavin et al., hep-ph/9502372 Comparison: Armesto, Cacciari, Dainese, Salgado, Wiedemann, PLB637 (06) 326 FONLL: electron spectrum may be ~50% c + ~50% b for 3 < p T < 8 GeV We investigated the DY component: < 10% up to 10 GeV Large uncertainty on b/c crossing point in p T : from scales/masses variation it changes from 3 to 9 GeV PHENIX electron cross section in pp now quite OK also at high p T PHENIX hep-ex/0508034 PHENIX, hep-ex/0609010 QM06 update ?

12. Prague, 07.11.2007 Andrea Dainese 12 R AA of c and b electrons at RHIC Armesto, Cacciari, Dainese, Salgado, Wiedemann, PLB637 (06) 326, Due to larger mass of b quark electron R AA increased to ~0.4 Mass uncertainty (in E loss) and scales uncertainty (in pQCD  b/c crossing) were studied c b c+b Theory predicts e R AA (~0.4) larger than  R AA (~0.2) e spectra in principle sensitive to mass hierarchy Perturbative uncertainty on the pp baseline comparable to model-intrinsic uncertainty in determination of Preliminary STAR data not conclusive for comparison with theory nucl-ex/0611018 QM06 Theory predicts e R AA (~0.4) larger than  R AA (~0.2) e spectra in principle sensitive to mass hierarchy Perturbative uncertainty on the pp baseline comparable to model-intrinsic uncertainty in determination of Final data (QM06): electron R AA tends to be overestimated Djordjevic, Gyulassy, Wicks, nucl-th/0512076

13. Prague, 07.11.2007 Andrea Dainese 13 QM06 R AA of c and b electrons at RHIC nucl-ex/0611018 (Adil & Vitev) Other approaches: include elastic E loss (Djordjevic, Gyulassy, Wicks) collisional dissociation of D/B mesons formed in the medium early after hard scattering (Adil & Vitev)

14. Prague, 07.11.2007 Andrea Dainese 14 Layout High-p T (heavy-flavour) particle production in hadronic collisions –from pp to AA– in factorized QCD pp baseline: pQCD calculations nuclear effects, in initial and final state What have we learnt at Tevatron and RHIC? What will be new at the LHC? What do we expect? What should we measure? Experimental Perspectives at the LHC

15. Prague, 07.11.2007 Andrea Dainese 15 Novelties at LHC (1): Hard Probes LHC: large hard cross sections! Our set of “tools” (probes) becomes richer quantitatively:qualitatively: heavy quarks  + jet correlations Z 0 + jet correlations LO pQCD by I. Vitev, hep-ph/0212109

16. Prague, 07.11.2007 Andrea Dainese 16 Heavy-quark production at the LHC pp: Important test of pQCD in a new energy domain Remember the “15-years saga of b production at Tevatron”* Baseline predictions: NLO (MNR code) in pp + binary scaling (shadowing included for PDFs in the Pb) ALICE baseline for charm / beauty: system :  s NN : Pb-Pb (0-5% centr.) 5.5 TeV p-Pb (min. bias) 8.8 TeV pp 14 TeV 4.3 / 0.27.2 / 0.311.2 / 0.5 115 / 4.60.8 / 0.030.16 / 0.007 0.65 / 0.800.84 / 0.90-- Theoretical uncertainty of a factor 2—3 (next slide) * M.Mangano MNR code: Mangano, Nason, Ridolfi, NPB373 (1992) 295.

17. Prague, 07.11.2007 Andrea Dainese 17 Theoretical Uncertainties (HERA-LHC Workshop) MNR code: Mangano, Nason, Ridolfi, NPB373 (1992) 295. Evaluation of theoretical uncertainties beautycharm CERN/LHCC 2005-014 hep-ph/0601164

18. Prague, 07.11.2007 Andrea Dainese 18 Model Comparisons (HERA-LHC Workshop) Compare predictions by several different models Good agreement between collinear factorization based calculations: FO NLO and FONLL k T factorization (CASCADE) higher at large p T beautycharm CERN/LHCC 2005-014 hep-ph/0601164

19. Prague, 07.11.2007 Andrea Dainese 19 Energy extrapolation via pQCD? Different systems (pp, p-Pb, Pb-Pb) will have different  s values Results in pp at 14 TeV will have to extrapolated to 5.5 TeV (Pb-Pb energy) to compute, e.g., nuclear modification factors R AA pQCD: “there ratio of results at 14 TeV/5.5 TeV has ‘small’ uncertainty” charm beauty  12%  8% MNR code: Mangano, Nason, Ridolfi, NPB373 (1992) 295.

20. Prague, 07.11.2007 Andrea Dainese 20 increasing  s Probe unexplored small-x region with HQs at low p T and/or forward y down to x~10 -4 with charm already at y=0 Eskola, Kolhinen, Vogt, PLB582 (2004) 157 Gotsmann, Levin, Maor, Naftali, hep-ph/0504040 Window on the rich phenomenology of high-density PDFs: gluon saturation / recombination effects Possible effect: enhancement of charm production at low p T w.r.t. to standard DGLAP-based predictions, even in pp!  c (DGLAP+non-linear)  c (DGLAP) Novelties at LHC (2): Small x

21. Prague, 07.11.2007 Andrea Dainese 21 Probing nuclear initial state PDFs with HQs Shadowing in pA (AA) CGC in pA (AA) Double parton scattering in pA c c Eskola, Kolhinen, Salgado, EPJC 9 (1999) 61

22. Prague, 07.11.2007 Andrea Dainese 22 Shadowing in pA (AA) CGC in pA (AA) Double parton scattering in pA Saturation scale Q s 2 (x) ~ xg(x)A/R A 2 ~ xg(x)A 1/3 At LHC for x~10 -4, Q s ~1.5-2 GeV > m c For m T,c ~ Q s, charm prod. CGC-dominated: scales with  N part in pA (not N coll ) harder p T spectra, since typical k T ~ Q s ~1.5 GeV, while in standard factorization k T ~  QCD ~0.2 GeV Probing nuclear initial state PDFs with HQs c c Kharzeev, Tuchin, NPA 735 (2004) 248 + LHC Predictions Workshop CGC: very similar RpA for p, D, B, ~indep. of pt and rapidity

23. Prague, 07.11.2007 Andrea Dainese 23 Shadowing in pA (AA) CGC in pA (AA) Double parton scattering in pA probe “many-body” PDFs normal and anomalous: different A dep. signature: events with “tagged” DD (can use D 0 +e + or e + e + ) and ch. conj. NB: there is a “background” from normal bb events, but it can be estimated from measured single inclusive b cross section predicted rate: cccc/cc ~ 10% (Treleani et al.) Probing nuclear initial state PDFs with HQs c c Cattaruzza, Del Fabbro, Treleani, PRD 70 (2004) 034022

24. Prague, 07.11.2007 Andrea Dainese 24 Heavy Quark Energy Loss at LHC ~100 cc pairs and ~5 bb pairs per central Pb-Pb collision Experiments will measure with good precision R AA for D and B, and for their decay leptons (as I’ll show in 5’) What can we learn from a comparative quenching study of massive and massless probes at the LHC?

25. Prague, 07.11.2007 Andrea Dainese 25 Heavy Flavour R AA at LHC Baseline: PYTHIA, with EKS98 shadowing, tuned to reproduce c and b p T distributions from NLO pQCD (MNR) (m/E)-dep. E loss with MNR: Mangano, Nason, Ridolfi, NPB 373 (1992) 295. Armesto, Dainese, Salgado, Wiedemann, PRD 71 (2005) 054027. * EKRT Saturation model: Eskola, Kajantie, Ruuskanen, Tuominen, NPB 570 (2000) 379.

26. Prague, 07.11.2007 Andrea Dainese 26 Colour-charge and mass dep. of E loss with Heavy-to-Light ratios at LHC Heavy-to-light ratios: Compare g  h, c  D and b  B mass effect For 10 < p T < 20 GeV, charm behaves like a m=0 quark, light-flv hadrons come mainly from gluons R D/h enhancement probes colour-charge dep. of E loss R B/h enhancement probes mass dep. of E loss Armesto, Dainese, Salgado, Wiedemann, PRD71 (2005) 054027

27. Prague, 07.11.2007 Andrea Dainese 27 LHC: Beauty-to-Charm ratio R B/D Compare c and b: same colour charge Mass effect  Enhancement of factor ~2, independent of (for ) Adapted from Armesto, Dainese, Salgado, Wiedemann, PRD71 (2005) 054027

28. Prague, 07.11.2007 Andrea Dainese 28 b Energy loss: Use W-decay muons as a reference Conesa del Valle, Dainese, Ding, Martinez, Zhou, in preparation early measurement for all experiments at the LHC! single  R CP (p t )

29. Prague, 07.11.2007 Andrea Dainese 29 “American” predictions for R AA at LHC Vitev, Adil, “Last Call for LHC Predictions” workshopWicks, Gyulassy, “Last Call for LHC Predictions” workshop Radiative+Collisional E loss à la GLV D B D+B D and B meson formation and dissociation inside the medium

30. Prague, 07.11.2007 Andrea Dainese 30 Charm hadron ratios as probe of QGP properties Yields of charm hadrons within statistical hadronization model Rafelski, Kuznetsova, LHC Predictions Workshop Ratio D/D s as a probe of T at measured s/S (PYTHIA: 6.92!) 0.13PYTHIA: 0.19 Braun-Muntzinger, Stachel, LHC Predictions Workshop

31. Prague, 07.11.2007 Andrea Dainese 31 Azimuth. asymmetry: v 2 from flow v 2 of D and B mesons in non-central collisions tests: at low/moderate p t : recombination scenario, flow of c/b quarks (?), hence degree of thermalization of medium Model: mult. scattering in expanding QGP (  elliptic flow) hadronization via coalescence + fragmentation c: 15-20% b: 5% van Heese, Rapp, Greco, LHC Predictions Workshop

32. Prague, 07.11.2007 Andrea Dainese 32 Azimuth. asymmetry: v 2 from E loss v 2 of D and B mesons in non-central collisions tests at higher p t : path-length dependence of E loss in almond- shaped medium Model: Radiative E loss (BDMPS) RHIC LHC c: 5-10% Armesto, Cacciari, Dainese, Salgado, Wiedemann, PLB637 (06) 326 + LHC Predictions Workshop

33. Prague, 07.11.2007 Andrea Dainese 33 Layout High-p T (heavy-flavour) particle production in hadronic collisions –from pp to AA– in factorized QCD pp baseline: pQCD calculations nuclear effects, in initial and final state What have we learnt at Tevatron and RHIC? What will be new at the LHC? What do we expect? What should we measure? Experimental Perspectives at the LHC

34. Prague, 07.11.2007 Andrea Dainese 34 Experimental study of heavy flavours in AA at the LHC ATLAS CMS

35. Prague, 07.11.2007 Andrea Dainese 35 The ALICE Detector |  | < 0.9, B = 0.5 T TPC + silicon tracker ,  e, , K, p identification -4 <  < -2.5 muons ALICE Collaboration: >1000 people, 30 countries, ~ 90 Institutes Size: 16 x 26 meters Weight: 10,000 tons

36. Prague, 07.11.2007 Andrea Dainese 36 Getting Ready for Beam! Ready to move TPC (largest ever) installed, ITS moving in MUON arm: largest dipole ever

37. Prague, 07.11.2007 Andrea Dainese 37 Open charm and beauty TPC (tracking) TOF (K/  id) ITS (vertexing) K  D 0  K  D +  K  D s  KK  D*  D 0  D 0  K   c   Kp under study D 0  K  D +  K  D s  KK  D*  D 0  D 0  K   c   Kp under study B  e+X B   5 pr. B  J/  ee under study ITS (vertexing) TPC (tracking e/  id) TRD (e/  id) e TPC (tracking) ITS (vertexing) MUON (tracking,id)  B   +X D 0  K  D +  K  D s  KK  D*  D 0  D 0  K   c   Kp under study B  e+X B   5 pr. B  J/  ee under study

38. Prague, 07.11.2007 Andrea Dainese 38 Primary Vertex B e X d0d0 rec. track Vertexing: track d 0 resolution < 60  m (r  ) for p T > 1 GeV/c Resolution mainly provided by the 2 layers of silicon pixels PIXEL CELL z: 425  m r  : 50  m Two layers: r = 4 cm r = 7 cm  9.8 M

39. Prague, 07.11.2007 Andrea Dainese 39 pair of opposite-charge tracks with large impact parameters good pointing of reconstructed D momentum to the primary vertex D0D0 Charm reconstruction: D 0  K -  + & D +  K -  +  + Two vertexing algos with full error-matrix treatment Large combinatorial background (dN ch /dy=6000 in Pb-Pb simul.) Main selection: displaced-vertex selection Invariant mass analysis large distance (d PS ) between primary and secondary vertex good pointing of reconstructed D momentum to the primary vertex D+D+ 1 year at nominal luminosity (10 9 pp events, 10 7 central Pb-Pb events) 10 20 30 40 50 D+D+ D0D0

40. Prague, 07.11.2007 Andrea Dainese 40 Beauty in the barrel: displaced single electrons Primary Vertex B e X d0d0 rec. track ALICE has excellent electron identification capabilities (TRD + TPC) Displaced electrons from B decays can be tagged by an impact parameter cut electron

41. Prague, 07.11.2007 Andrea Dainese 41 Beauty in the barrel: multi-prong vertices, displaced J/  ee At the LHC, 20% of J/  from B decays measurement of b cross section Displaced di-electrons from J/  from B decays J/   e + e - primary secondary J/  pseudoproper decay time (p t >5GeV) Beauty decays in many (4-6) charged particles

42. Prague, 07.11.2007 Andrea Dainese 42 Beauty via (forward) muons inner bars: stat. errors outer bars: syst. errors Muons “identified” in the forward spectrometer (-4 <  < -2.5) Pb-Pb 0-5%  single muons in the spectrometer: beauty dominates for p t > 2-3 GeV/c

43. Prague, 07.11.2007 Andrea Dainese 43 Calibrating the probe (pp,  s = 14 TeV) D 0  K  B  e + X measured at 14 TeV, then scaled by pQCD to 5.5 TeV Expected sensitivity in comparison to pQCD: 1 year at nominal luminosity (10 9 pp events)

44. Prague, 07.11.2007 Andrea Dainese 44 Charm and Beauty E Loss : R AA m b = 4.8 GeV D 0  K  B  e + X 1 year at nominal luminosity (10 7 central Pb-Pb events, 10 9 pp events) D +  K  m C = 1.2 GeV m C = 0 B  e E loss calc.: Armesto, Dainese, Salgado, Wiedemann

45. Prague, 07.11.2007 Andrea Dainese 45 Heavy-to-light ratios 1 year at nominal luminosity (10 7 central Pb-Pb events, 10 9 pp events) probes colour-charge dep. of QCD energy loss probes mass dep. of QCD energy loss E loss calc.: Armesto, Dainese, Salgado, Wiedemann

46. Prague, 07.11.2007 Andrea Dainese 46 Charm v 2 : D + example First estimate of statistical errors on D + v 2 : best sensitivity at intermediate p t : 3 – 7 GeV/c  charm recombination Under study: performance with D 0 + D + 2  10 7 min.bias evts 2  10 7 6<b<9 fm evts v 2 calc. from Ko et al.

47. Prague, 07.11.2007 Andrea Dainese 47 Conclusions LHC: heavy quarks factory! Heavy quarks as probes of QCD in extreme conditions low p t : probe small-x structure of p and nucleus intermediate p t : probe medium thermalisation (reco/flow) high p t : probe medium density via energy loss ALICE in excellent position: dedicated detectors (ITS, TRD, MUON) promising performance for all key measurements

48. Prague, 07.11.2007 Andrea Dainese 48 Appendix: QUARKONIA at LHC

49. Prague, 07.11.2007 Andrea Dainese 49  H.Satz Quarkonia at LHC:  (cc) J/  suppression & regeneration?  c,  ’ suppression (J/  T D ~ 1.5-2 T c )? Satz, CERN Heavy Ion Forum, 09/06/05 SPS RHIC LHC 30 enhanced suppression enhanced regeneration T LHC >> J/  T D Wong, PRC 72 (2005) 034906 Alberico, hep-ph/0507084 Becattini, PRL95 (05) 022301 Statistical hadronization: huge enhancements for  cc,  cc, B c,  ccc e.g.  1000 for  ccc /D from pp to Pb-Pb

50. Prague, 07.11.2007 Andrea Dainese 50  production RHICLHC Vogt, hep-ph/0205330 Quarkonia at LHC:  (bb)  d  /dy @ LHC ~20 x RHIC  melts only at LHC  ’ T D ~ J/  T D Wong, PRC 72 (2005) 034906 Alberico, hep-ph/0507084 Small  regeneration Grandchamp et al., hep-ph/0507314  ’ can unravel J/  suppression vs. regeneration Gunion and Vogt, NPB 492 (1997) 301  ’/  vs p t sensitive to system temp. & size

51. Prague, 07.11.2007 Andrea Dainese 51 Quarkonia at LHC: experimental challenges Important contribution to  production from B  J/  (  ’) + X ~20% of J/  ~40% of  ’ Normalization:  Drell-Yan not available for normalization (from qq, while quarkonia from gg at LHC; and small cross section at LHC)  W, Z?  Different Q 2, x  Open heavy flavour, but …  Energy loss?  Thermal charm production?  Possible alternative: R AA (à la PHENIX) Need to measure this!

52. Prague, 07.11.2007 Andrea Dainese 52 ITS (vertexing) TPC (tracking) TRD (e/  id) MUON (tracking,id)  e e  Quarkonia Measured both in the di-electron (midrapidity, TRD) and di-muon (forward rapidity, MUON) channel

53. Prague, 07.11.2007 Andrea Dainese 53 +-+- +-+- +-+- e+e-e+e- Quarkonia acceptances -4<  <-2.5  J/  -4<  <-2.5 acceptance (%) J/  

54. Prague, 07.11.2007 Andrea Dainese 54 Particle Charmonia  +  - Charmonia e + e - Bottonia  +  - Bottonia e + e - Bkg- subtracted mass plot acc.  -4 <  < -2.5|  | < 0.9-4 <  < -2.5|  | < 0.9 M res.65 MeV35 MeV90 MeV J/  150,  ’ 7 J/  245  30,  ’ 12,  ’’ 8  21,  ’ 8 perf. , ?  ’ , ??  ’ ,  ’, ?  ’’ , ?  ’, no  ’’ ptpt J/  0-20 GeV J/  0-10 GeV  0-8 GeV-- Quarkonia Performance Bkg input: dN ch /dy=4000 in central Pb-Pb. for 1 month

55. Prague, 07.11.2007 Andrea Dainese 55 Medium effect on Quarkonia: Quarkonia/BB, Quarkonia R AA Normalization of quarkonia yields: BB yield (from intermediate-mass di-leptons), but b E loss? Possible alternative: R AA (à la PHENIX), but different c.m.s. energy, need p-Pb for initial-state effects Plots for     channel

56. Prague, 07.11.2007 Andrea Dainese 56 EXTRA SLIDES

57. Prague, 07.11.2007 Andrea Dainese 57 LHC running conditions  Ldt = 5.10 26 cm -2 s -1 x 10 6 s 5.10 32 cm -2 PbPb run, 5.5 TeV N PbPb collisions = 2.10 9 collisions  Ldt dt = 3.10 30 cm -2 s -1 x 10 7 s 5.10 37 cm -2 for pp run, 14 TeV N pp collisions = 2.10 12 collisions Muon triggers: ~ 100% efficiency, ~ 1kHz Electron triggers: Bandwidth limitation N PbPb central = 2.10 8 collisions  Muon triggers: ~ 100% efficiency, < 1kHz Pb-PB nominal run pp nominal run Electron triggers: ~ 50% efficiency of TRD L1 20 physics events per event Hadron triggers: N PbPb central = 2.10 7 collisions Hadron triggers: N pp minb = 2.10 9 collisions 

58. Prague, 07.11.2007 Andrea Dainese 58 D 0  K -  + : Selection of D 0 candidates increase S/B by factor ~10 3 ! central Pb-Pb events

59. Prague, 07.11.2007 Andrea Dainese 59 Expected Sensitivity to R AA D 0  K  B  e + X 15%systematic from efficiency corrections15% 12%theory uncertainty in energy extrapolation8% --charm electron subtraction~5% 8%normalization error ( )8%