1. 5/25/2009Mike Leitch1 Understanding J/Ψ Suppression Cold Nuclear Matter (CNM) extrapolations from p(d)+A to A+A

2. Present (PPG078) CNM Constraints on A+A data CNM effects (EKS shadowing + dissociation from fits to d+Au data, with R. Vogt calculations) give large fraction of observed Au+Au suppression, especially at mid-rapidity more accurate d+Au constraint soon from 2008 data d+Au small-x (shadowing region) PRC 77,024912(2008) R dAu 5/25/20092Mike Leitch & Erratum: arXiv:0903.4845 Au+Au mid-rapidity Au+Au forward-rapidity R AA EKS shadowing band

3. New 2008 d+Au J/Ψ data - RCP Initial d+Au J/Ψ update from new 2008 data (~30x 2003) R CP pretty flat vs centrality at backward rapidity; but falls at forward rapidity (small-x) more soon – precision statistics requires precision systematics & careful analysis EKS σ = 0,1,2,3,4,…15 5/25/20093Mike Leitch

4. 6/24/2009Mike Leitch4 similar to before, use models with shadowing & absorption/breakup but allow effective breakup cross section to vary with rapidity to obtain good description of data for projections to A+A get “  breakup (y)”; compare to E866/NuSea & HERA-B Lourenco, Vogt, Woehri - arXiv:0901.3054 common trend, with large increasing effective breakup cross section at large positive rapidity need additional physics in CNM model – e.g. initial-state dE/dx with EKS shadowing with NDSG shadowing New CNM fits using 2008 PHENIX d+Au Rcp

5. 6/24/2009Mike Leitch5 Cross Check - Comparision of New Effective Breakup Cross Section fits to published 2003 d+Au R dAu Results Fairly consistent with RdAu from old 2003 data PRC 77,024912(2008)

6. 6/24/2009Mike Leitch6 Survival Probability after dividing out CNM “extrapolation” The relation between the charged multiplicity and N Part is obtained AuAu  using PHOBOS data (Phys.Rev.C65 061901 (2002) PbPb  using NA50 data (Phys.Lett.B 530 1-4 (2002) 43-55) Good agreement between PbPb and AuAu Results are shown as a function of a the multiplicity of charged particles (~ energy density, assuming  SPS ~  RHIC )

7. 5/25/2009Mike Leitch7  Both Pb-Pb and Au-Au seem to depart from the reference curve at N Part ~200  For central collisions more important suppression in Au-Au with respect to Pb-Pb Measured/Expected SPS results are compared with AuAu RHIC R AA results normalized to R AA (CNM) Comparison with new RHIC results

8. 5/25/2009Mike Leitch8 Open Charm Nuclear Dependence from FNAL-E789/E866

9. 6/24/2009Mike Leitch9 Fermilab E789: D 0 & B  J/ψ X (charm & beauty using silicon) Dimuon spectrometer + 16-plane, 50  m pitch/8.5k strip silicon vertex detector upstreamdownstream B  J/ψ + X D 0 -> K  K+-K+- K-+K-+ Mass (GeV/c 2 )

10. 6/24/2009Mike Leitch10 E866/NuSea Open Charm Measurement Dump Target target  dump  hadronic cocktail explains ~30% of target & <5% of dump  ’s as expected since dump absorbs light hadrons before they can decay charm decays consistent between Cu target and Cu dump use same method for Be to get nuclear dependence beam data hadrons charm E866/NuSea 800 GeV p+A S. Klinksiek thesis - hep-ex_0609002 paper in preparation 2.34 m charm ~ 3.3 hadrons charm ~ 20 hadrons

11. 6/24/2009Mike Leitch11 Rapidity dependence of open charm Open-charm p+A nuclear dependence (single-  p T > 1 GeV/c) – very similar to that of J/Ψ dominant effects are in the initial state e.g. shadowing, dE/dx, Cronin weaker open-charm suppression at y=0 attributed to lack of absorption for open charm E866/NuSea 800 GeV p+A

12. 6/24/2009Mike Leitch12

13. 5/25/2009Mike Leitch13

14. PHENIX Au+Au data shows suppression at mid-rapidity about the same as seen at the SPS at lower energy but stronger suppression at forward rapidity. Forward/Mid R AA ratio looks flat above a centrality with N part = 100 Several scenarios may contribute: Cold nuclear matter (CNM) effects important, need better constraint Sequential suppression QGP screening only of  C &  ’- removing their feed-down contribution to J/  at both SPS & RHIC Regeneration models give enhancement that compensates for screening PHENIX A+A Data and Features Centrality (N part ) 5/25/200914Mike Leitch

15. Looking for the cold nuclear matter baseline for J/ψ production at RHIC Tony Frawley Florida State University ECT, Trento May 26, 2009

16. Tony Frawley, FSU16 Many thanks for contributions/help from: Ramona Vogt Mike Leitch Alex Linden Levy Jamie Nagle Darren McGlinchey

17. May 26, 2009Tony Frawley, FSU17 The quarkonium plan SpeciesPurpose p+pQuarkonium production mechanisms Baseline cross sections for heavy ions d+Au Cold nuclear matter effects Baseline CNM R AA for heavy ions Cu+CuHot nuclear matter effects near T C Au+AuHot nuclear matter effects well above T C

18. May 26, 2009Tony Frawley, FSU18 The PHENIX Detector J/ψ→e + e - -0.35 < y < 0.35 J/ψ→μ + μ - 1.2 < |y| < 2.2

19. May 26, 2009Tony Frawley, FSU19 Brief review of the relevant J/ψ data Au+Au R AA Run 4 Au+Au+ Run 5 p+p Cu+Cu R AA Run 5 Cu+Cu + Run 5 p+p d+Au R CP Run 8 d+Au To come: Run 8 R dAu with Run 6 pp reference

20. May 26, 2009Tony Frawley, FSU20 Reference data – Run 5 p+p PHENIX, PRL98, 2002 (2007) This is the reference data set for all nuclear modification factors shown here.

21. May 26, 2009Tony Frawley, FSU21 Cu+Cu and Au+Au R AA Phys. Rev. Lett. 101, 122301 (2008) The Npart dependence of Au+Au and Cu+Cu is consistent. Note the smaller systematic uncertainties for the Cu+Cu data. This is primarily due to smaller uncertainties on Ncoll from the Glauber calculation. Thus the Cu+Cu data will be much better for studying the onset of hot nuclear matter effects.

22. May 26, 2009Tony Frawley, FSU22 Au+Au R AA PHENIX – reference here The stronger Au+Au suppression at forward/backward rapidity has generated considerable interest. But what is the expected suppression due to cold nuclear matter effects?

23. May 26, 2009Tony Frawley, FSU23 d+Au R CP The first results for d+Au from Run 8, shown at QM09. Four centrality bins to make three R CP points:

24. May 26, 2009Tony Frawley, FSU24 What can we learn from the existing charmonium R AA data? The heavy ion charmonium data alone have not taught us as much as we would like, because of serious uncertainties caused by: 1) Poorly known initial state effects at RHIC: Break up cross section for collisions with nucleons. Shadowing. Other effects? Initial state energy loss? 2) Poorly known open charm production cross sections. Thus the trade-off between coalescence and destruction is difficult to illuminate experimentally. To try to make inroads on 1), we start from the most recent d+Au data set: – Run 8 d+Au First we briefly review previous attempts to use Run 3 d+Au data for this.

25. May 26, 2009Tony Frawley, FSU25 Estimating the CNM R AA from Run 3 d+Au data - 1 This has been done before in three ways: 1) PHENIX (Phys. Rev. C 77, 024912 (2008) and erratum arXiv:0903.4845) fitted Run 3 R dAu using a single σ breakup at all rapidities + EKS98/nDSg shadowing calculations by Ramona Vogt. The CNM RAA was estimated using calculations of R AA for Cu+Cu and Au+Au by Ramona, using the fitted σ breakup + EKS98/nDSg. However (Phys. Rev. Lett. 101, 122301 (2008)PPG071), when a single σ breakup is used at all rapidities the ratio of the predicted y=0 to |y|=1.7 CNM RAA values is just a prediction of the shadowing model. Therefore this is not a good way to use the R dAu data to test if the increased suppression at |y|=1.7 is due to CNM effects. R AA Au+Au mid-rapidity Au+Au forward-rapidity R AA EKS shadowin g band

26. May 26, 2009Tony Frawley, FSU26 Estimating the CNM R AA from Run 3 d+Au data - 2 2) Raphael Granier de Cassagnac (J. Phys. G34, S955 (2007)) used direct folding of the R dAu data, with some assumptions, to predict the CNM R AA for Au+Au. This works only for Au+Au, since R dAu is used directly. This approach produces completely independent CNM R AA values at y=0 and |y|=1.7 – which is very good. But because of the low statistical precision of the Run 3 d+Au data, the results are inconclusive. This approach cannot be used with d+Au R CP data, nor can it be used to estimate a CNM R AA baseline for Cu+Cu.

27. May 26, 2009Tony Frawley, FSU27 Estimating the CNM R AA from Run 3 d+Au data - 3 Phys. Rev. Lett. 101, 122301 (2008) 3) The PHENIX R dAu data were fitted separately at y=0 and |y|=1.7 with σ breakup + EKS98/nDSg calculations by Ramona. The CNM R AA was predicted for Cu+Cu and Au+Au independently at y=0 and |y|=1.7 using calculations by Ramona. While this makes the ratio of the estimated CNM R AA at y=0 and |y|=1.7 sensitive to the R dAu data, it still assumes the forward and backward rapidity data have the same σ breakup. We will see this is not justified. NOTE: The uncertainty bands here are underestimated due to the fitting error that was corrected for 1). Not fixed here yet!

28. May 26, 2009Tony Frawley, FSU28 Fitting the Run 8 d+Au R CP We want to parameterize the d+Au R CP data so that we can predict the heavy ion R AA that would result from p+A physics only. Fit R CP vs centrality independently at each rapidity using calculations of R dAu vs impact parameter by Ramona Vogt that include: σ breakup for collisions of (forming) J/ψ with nucleons (0-15 mb, 1 mb steps). A shadowing model – EKS98 and nDSg are used here. Convert R dAu vs impact parameter to R dAu vs centrality using PHENIX Glauber impact parameter distribution for each dAu centrality bin. Fit procedure: Fit R CP vs centrality using only uncertainties that are uncorrelated in rapidity. Vary R CP by +/- 1σ in uncertainties that are correlated in rapidity, and refit. Vary R CP by +/- 1σ in uncertainties that are global with rapidity and refit. Uncertainties are shown respectively as bars, boxes, and a global number.

29. May 26, 2009Tony Frawley, FSU29 Fits to d+Au R CP – example for EKS98 Integrated for each muon arm

30. May 26, 2009Tony Frawley, FSU30 σ breakup vs y from d+Au R CP fits with EKS98 and nDSg

31. May 26, 2009Tony Frawley, FSU31 Comparison with lower energy data – EKS98 fits Lourenco, Vogt and Woehri (JHEP 02 (2009) 014) published the effective breakup cross section vs y from fits to E866 and HERA-B data. Our results from 200 GeV are shown here compared with their results for the EKS98 case. For y > 1.2 the 200 GeV data follow the trend observed at lower energy remarkably closely!

32. May 26, 2009Tony Frawley, FSU32 Comparison with lower energy data – nDSG fits Note that the effective breakup cross section is significantly lower for y < 1.2. But for y > 1.2 there is little difference from the EKS case.

33. May 26, 2009Tony Frawley, FSU33 Sanity check! Comparision of new effective breakup cross section fits from R CP to published 2003 d+Au R dAu results From the talk by Mike Leitch. Fairly consistent with centrality integrated RdAu from old 2003 data PRC 77,024912(2008)

34. May 26, 2009Tony Frawley, FSU34 Parameterize d+Au R CP at |y|= 0, 1.7 – EKS98 Integrated for each muon arm

35. May 26, 2009Tony Frawley, FSU35 Effective σ breakup used in Glauber calculations |y| = 0, 1.7

36. May 26, 2009Tony Frawley, FSU36 Cold Nuclear Matter R AA for heavy ions Having “calibrated” the Vogt calculations at each rapidity, we estimate the CNM R AA using the results from the dAu R CP fits. To do this, we use a Glauber calculation for Au+Au that reproduces well the average Npart and Ncoll values for the centrality bins used by PHENIX. In the Glauber calculation: Each nuclear collision is placed in a centrality bin according to Npart. For each nucleon-nucleon collision: Determine impact parameter b1 of nucleon 1 in its target nucleus. Determine impact parameter b2 of nucleon 2 in its target nucleus. Add to the accumulated RAA: RdAu(b1,y=0) * RdAu(b2,y=0) Add to the accumulated RAA: RdAu(b1,y=-1.75) * RdAu(b2,y=1.75) After processing all events, print out at y=0 and y=1.7 for centrality bin j: Nevts[j], Σ(RAA[j])/Nevts[j], Σ(Ncoll[j])/Nevts[j], Σ(Npart[j])/Nevts[j]

37. May 26, 2009Tony Frawley, FSU37 Estimation of uncertainties The CNM R AA is calculated for the central fitted σ breakup and for +/- 1σ in the type A (uncorrelated in rapidity) uncertainty and for +/- 1σ in the type B (correlated in rapidity) uncertainty. The type A uncertainty is shown as a vertical bar, and the type B as a box.

38. May 26, 2009Tony Frawley, FSU38 Heavy ion CNM baseline R AA – EKS98 parameterization

39. May 26, 2009Tony Frawley, FSU39 Heavy ion CNM baseline R AA – nDSg parameterization

40. May 26, 2009Tony Frawley, FSU40 Calculating the heavy ion R AA “survival probability” Now we can calculate the ratio R AA /R AA (CNM) from the measured R AA and the estimated R AA (CNM) shown on the previous slides. In the following plots the uncertainty in R AA /R AA (CNM) due to the uncorrelated (mostly statistical) uncertainty in the measured R AA is shown as a bar, the correlated uncertainty in the measured R AA us shown as a narrow box, and the uncertainty due to the estimated CNM R AA is shown as a wider box.

41. May 26, 2009Tony Frawley, FSU41 Heavy ion “survival probability” at y=0 (EKS example)

42. May 26, 2009Tony Frawley, FSU42 Heavy ion “survival probability” at |y| = 1.7 (EKS example)

43. May 26, 2009Tony Frawley, FSU43 Heavy ion “survival probability” - EKS98 parameterization

44. May 26, 2009Tony Frawley, FSU44 Heavy ion “survival probability” - nDSg parameterization

45. May 26, 2009Tony Frawley, FSU45 Comments We are just starting to try to understand the d+Au data and their implications for heavy ions. Keep several things in mind about what was done here: We assume that we can isolate hot nuclear matter effects by calculating R AA due to a (Glauber guided) superposition of d+Au collisions. Perhaps not! The role of Glauber uncertainties (mostly Ncoll) needs to be understood in detail. The systematic uncertainties should be considered tentative until then. We believe that fitting the R dAu data, rather than R CP, will provide greater precision when estimating the CNM baseline R AA for Au+Au and Cu+Cu. Although the parameterization at each rapidity is precise, it would be more satisfying if the model worked well over the full d+Au rapidity range! We need to repeat this exercise for the Cu+Cu data (easy enough to do, did not have time yet).

46. May 26, 2009Tony Frawley, FSU46 Summary The PHENIX d+Au data at 200 GeV seem to follow the trend observed at lower energy of a rapid rise in the effective σ breakup at forward rapidity. The effective σ breakup appears to be roughly constant below y ~ 1.25 at 200 GeV. The R AA (CNM) estimated from the fits to the R dAu data show significantly stronger suppression at |y|=1.7 than at y=0. The measured suppression beyond the estimated R AA (CNM) values, presumably due to hot nuclear matter effects, seems to be very similar at y=0 and |y|=1.7 at about 50%.

47. May 26, 2009Tony Frawley, FSU47 What next Calculate R AA (CNM) for Cu+Cu. Investigate the transverse momentum dependence. Understand the role of Ncoll uncertainties better. Do it all again with R dAu instead of R CP.

48. May 26, 2009Tony Frawley, FSU48 Backup

49. May 26, 2009Tony Frawley, FSU49 EPS08 parameterization

50. May 26, 2009Tony Frawley, FSU50 Existing RHIC Data - Au+Au

51. May 26, 2009Tony Frawley, FSU51 Existing RHIC Data - Cu+Cu

52. May 26, 2009Tony Frawley, FSU52 Reference data: Run 6 p+p will be used for R dAu The best p+p data set that has been analyzed so far is from Run 6.