1. Quarkonium results: lessons from LHC run-1 1 E. Scomparin (INFN-Torino) Trento, March 16-20 2015  Introduction, pre-LHC summary  LHC run-1  substantial progress on charmonium/bottomonium studies!  Open points and prospects for run-2  Conclusions

2. A lively topic 2  Quarkonium suppression as a “QGP thermometer” My own “thermometer” of the interest of the community in quarkonium studies Number of citations of the seminal Matsui’s and Satz’s paper 09/11/09 1279 06/12/10 1344 22/11/11 1447 09/11/12 1644 17/11/14 2041 14/03/07 1176 Citations doubled in the last ~8 years Still a very “hot” topic! TcTc

3. ~30 years of experiments 3 (peripheral) (central) From the ‘80s… …until today! SPS (NA38-NA50-NA60) RHIC (PHENIX-STAR) LHC (ALICE-CMS) C. Baglin et al. (NA38), Phys. Lett. B220(1989) 471 CMS Coll., PRL 109(2011) 222301

4. HI studies: reference processes 4  Choice of “suitable” reference process for the modification of the quarkonium yields proved to be crucial (and much debated!)  SPS energy  Drell-Yan process  Cancellation of syst. uncertainties  No initial/final state effects in the explored kinematic region  Small statistics  RHIC, LHC energy  R AA  Limited cancellation of uncertainties  Does not account for initial/final state effects not related to the medium  Precise reference data can be collected  Ideal reference  Normalization to open charm  Most “natural” reference  initial state effects cancel out  Differential comparisons not straightforward  Charm energy loss  shifts D-meson p T  J/ suppression  removes yield  Open charm data have non-negligible uncertainties (especially at low p T ) q q  ++ --

5. HI studies: role of CNM 5  Considered as a crucial step for the understanding of A-A results  However  Description of pA data in terms of various CNM effects is difficult  Extrapolation pA  AA can be effect-dependent and/or model dependent  At SPS  Use of effective quantity  abs (break-up cross section) tuned on pA data and then directly extrapolated to A-A (via L-variable)  At RHIC  Combination of shadowing (factorized out using nuclear PDFs parameterizations) and break-up  Centrality dependence exhibits surprising (understood?) effects  At LHC  Break-up cross section negligible  (Coherent) energy loss effects become important  First attempts (see later) at an extrapolation pA  AA 5 p c c g J/,  c,...

6. 6 Low energy results: J/ from SPS & RHIC SPS (NA38, NA50, NA60) s NN = 17 GeV First evidence of anomalous suppression (i.e. beyond CNM expectations) in Pb-Pb collisions ~30% suppression compatible with (2S) and  c decays RHIC (PHENIX, STAR) s NN = 39, 62.4, 200 GeV suppression, with strong rapidity dependence, in Au-Au at s= 200 GeV R.Arnaldi et al.(NA60) NPA830 (2009) 345cA. Adare et al. (PHENIX) PRC84(2011) 054912

7. 7 Low energy results: J/ from SPS & RHIC Comparison of SPS and RHIC results Good agreement between SPS and RHIC patterns if cold nuclear matter effects are taken into account N.Brambilla et al. (QWG) EPJC71 (2011) 1534 Understanding cold nuclear matter effects and feed-down is essential for a quantitative assessment of charmonium physics  Compensation of suppression/recombination effects?  Suppression of  c and (2S) w/o recombination?

8. 8 Low energy results: (2S) from SPS & RHIC SPS (NA50) pA, AA @ s NN = 17 GeV RHIC (PHENIX) d-Au @s NN = 200 GeV NA50 Coll., Eur. Phys. J. C 49, 559 (2007) (2S) is more suppressed than J/ already in pA collisions and the suppression increases in Pb-Pb PHENIX Coll., PRL 111, 202301 (2013) unexpected (2S) suppression (forms outside nucleus) stronger than the J/ one in central d-Au Pb-Pb p-A S-U

9. 9 Low energy results:  from SPS & RHIC SPS (NA50) pA, s NN =29 GeV First  measurement at SPS energies. Hint for no strong medium effects on (1S+2S+3S) in pA RHIC (PHENIX, STAR) dAu, Au-Au s NN = 200 GeV B. Alessandro (NA50 Coll), PLB 635(2006) 260  R AA compatible with suppression of excited states, with large uncertainties A.Adare (PHENIX Coll.), 1404.2246 L. Adamczyk (STAR Coll.) PLB 735 (2014) 127

10. Lessons from low-energy A-A… 10  Suppression effect on J/ beyond CNM undisputable at both SPS and RHIC  Common interpretation: mainly related to screening/dissociation in hot (deconfined) matter  Role of J/ regeneration tiny (if any) at SPS energy  Quantitatively much debated at RHIC energy  Energy scan very interesting in principle (onset of suppression), but only top energy was explored at the SPS (new NA60+ experiment?)  Results at s=39 and 62.4 GeV suffer from large uncertainties (absence of proper reference data)  (2S) largely suppressed in A-A compared to J/ at SPS energy  Commonly seen as an effect of its weak binding   resonances out of SPS reach  Intriguing results at RHIC, first recent attempt to separate 1S (STAR)  Suppression compatible with complete 2S+3S melting, 1S suppression only for central events

11. …and questions for LHC 11 1) Evidence for charmonia (re)combination: now or never!   (3S)  b (2P)  (2S)  b (1P)  (1S) 2) A detailed study of bottomonium suppression Do we see enhancement vs centrality ? Do we see J/ flow? Do we see softer p T distributions? Do we see sequential suppression ? (as recombination does not play a role)

12. The main actors 12 CMS (high p T ) ALICE (low p T )  CMS  Excellent mass resolution for muons(35 MeV for J/)  Prompt vs non-prompt  Cut low-p T charmonia  ALICE  Access mid- and forward- rapidity (e + e - and  +  respectively)  Good mass resolution for J/ (~70 MeV for muons, ~30 MeV for electrons)  Full p T acceptance in the whole y-range  Prompt vs non-prompt at y=0 J/ ATLAS CMS LHCb ALICE

13. The low p T region: ALICE 13 B. Abelev et al., ALICE Phys. Lett. B 734 (2014) 314  Centrality dependence of the nuclear modification factor studied at both central and forward rapidities Inclusive J/ R AA Small effect of non-prompt contribution on the inclusive R AA  At forward y, R AA flattens for N part  100  Central and forward rapidity suppressions compatible within uncertainties Global syst: 13% e + e - 15%  +  - Forward y: No B suppression  R AA prompt ~0.94R AA incl Full B suppression  R AA prompt ~1.07R AA incl Central y: No B suppression  R AA prompt ~0.91R AA incl Full B suppression  R AA prompt ~1.17R AA incl

14. Low p T : comparison ALICE vs PHENIX 14  Comparison with PHENIX  Stronger centrality dependence at lower energy  Systematically larger R AA values for central events in ALICE  Behaviour qualitatively expected in a (re)generation scenario  Look at the p T dependence of the suppression

15. 15 Comparison to theory calculations: Models including a large fraction (> 50% in central collisions) of J/ produced from (re)combination or models with all J/ produced at hadronization provide a reasonable description of ALICE results Still rather large theory uncertainties: models will benefit from a precise measurement of  cc and from cold nuclear matter evaluation J/ R AA vs centrality: theory comparison

16. A (re)generation “signature”: the p T dependence of R AA 16  At low p T, for central events, the suppression is up to 4 times larger at PHENIX, compared to ALICE  Strong indication for (re)generation Global syst: 8% ALICE 10% PHENIX

17. Moving to higher p T : CMS vs ALICE 17  Complementary y-coverage: 2.5<y<4 (ALICE) vs 1)1.6<|y|<2.4 (CMS, left) 2)|y|<2.4 (CMS, right)  Qualitative agreement in the common p T range B. Abelev et al., ALICE Phys. Lett. B 734 (2014) 314

18. CMS results: prompt J/ at high p T 18 CMS PAS HIN-2012-014 CMS-PAS HIN-12-2014  Striking difference with respect to ALICE  No saturation of the suppression vs centrality  High-p T RHIC results show weaker suppression  No significant p T dependence from 6.5 GeV/c onwards  (Re)generation processes expected to be negligible

19. CMS results: prompt J/ at high p T 19  Striking difference with respect to ALICE  No saturation of the suppression vs centrality  High-p T RHIC results show weaker suppression  No significant p T dependence from 6.5 GeV/c onwards  (Re)generation processes expected to be negligible CMS PAS HIN-2012-014 CMS-PAS HIN-12-2014

20. 20 The contribution of J/ from (re)combination should lead to a significant elliptic flow signal at LHC energy J/ flow CMS measures a significant v 2 in a region where (re)combination should be negligible  due to path-length dependence of J/ suppression STAR found v 2 consistent with 0 ALICE measures v 2 (with a significance up to 3 for chosen kinematic/centrality selections) in agreement with transport models including (re)combination b diffusion ALICE Coll., Phys. Rev. Lett. 111 (2013) 162301

21. Moving to p-Pb J/ results: R pPb vs y 21  ALICE and LHCb results in good agreement  Strong suppression at forward and mid-y: no suppression at backward y  Data are consistent with models including shadowing and/or energy loss  Color Glass Condensates (CGC) inspired models underestimate data  Dissociation cross section  abs <2 mb cannot be excluded LHCb Coll., JHEP 02 (2014) 072 ALICE Coll., JHEP 02 (2014) 073

22. R pPb vs p T 22  The p T dependence of J/ R pPb has been studied in the three y ranges backward-y mid-y forward-y  backward-y: negligible p T dependence, R pA compatible with unity  mid-y: small p T dependence, R pA compatible with unity for p T >3GeV/c  forward-y: strong R pA increase with p T  Comparison with theory:  Data consistent with pure shadowing calculations and with coherent energy loss models (overestimating J/ suppression at low p T, forward-y)  CGC calculation overestimate suppression at forward-y

23. Event activity dependence: Q pPb 23  At forward-y, strong J/ Q pA decrease from low to high event activity  At backward-y, Q pA consistent with unity, event activity dependence not very significant

24. CNM effects: from p-Pb to Pb-Pb 24  x-values in Pb-Pb s NN =2.76 TeV, 2.5<y cms <4  x-values in p-Pb s NN =5.02 TeV, 2.03 < y cms < 3.53  210 -5 < x < 810 -5  x-values in p-Pb s NN =5.02 TeV, -4.46 < y cms < -2.96  110 -2 < x < 510 -2  Partial compensation between s NN shift and y-shift  If CNM effects are dominated by shadowing  R PbPb CNM = R pPb  R Pbp = 0.75 ± 0.10 ± 0.12  R PbPb meas = 0.57 ± 0.01 ± 0.09 “compatible” within 1- 210 -5 < x < 910 -5 110 -2 < x < 610 -2  Same kind of “agreement” in the energy loss approach …which does not exclude hot matter effects which partly compensate each other F. Arleo and S. Peigne, arXiv:1407.5054

25. 25 p T -dependence pA AA Pb-Pb p-Pb Pb-Pb p-Pb  Perform the extrapolation as a function of p T  No more “agreement” between Pb-Pb and CNM extrapolations  High-p T suppression is not related to CNM effects  At low p T CNM suppression is of the same size of the effects observed in Pb-Pb: recombination ?

26. Comparing charmonia and open charm: p-Pb 26  ALICE p-Pb results, mid-rapidity, p T integrated R pPb J/ = 0.73  0.08  0.15R pPb D = 0.85  0.05  0.11 (weighted average of p T differential points using FONLL cross section (no FONLL unc.) and R pPb (0-1)=R pPb (1-2) ) Assuming R pPb (0-1) = 0.4 R pPb D = 0.82  0.05  0.11 Within uncertainties (and with reasonable extrapolations to p T =0), CNM effects on integrated J/ and D-mesons production have the same size ALICE Coll., PRL 113 (2014) 232301

27. Comparing charmonia and open charm: p-Pb  ALICE p-Pb results, mid-rapidity, p T differential  Bin-to-bin comparison less straightforward g g D D g g J/ At fixed p T, gluon kinematics can be (very) different for single D and J/ ALICE Coll., PRL 113 (2014) 232301

28. Comparing charmonia and open charm: p-Pb 28  Single muon results available for p T > 2 GeV/c  (More) difficult to extract an integrated R pPb  Bin-to-bin comparison not straightforward p-going direction

29. Comparing charmonia and open charm: p-Pb 29  Single muon results available for p T > 2 GeV/c  (More) difficult to extract an integrated R pPb  Bin-to-bin comparison not straightforward Pb-going direction

30. Comparing charmonia and open charm: Pb-Pb 30 R PbPb D = 0.51  0.08  0.09 (weighted average of p T differential points using FONLL cross section (no FONLL unc.) and R pPb (0-1)=R pPb (1-2) ) Assuming R pPb (0-1) = 1 R PbPb D = 0.63  0.08  0.10 R PbPb J/ = 0.73 ± 0.09 ± 0.06 ± 0.09 0-10% Good compatibility (especially assuming R pPb (0-1) = 1) between D and J/  Suppression and regeneration balance  Warning: D S,  c (not included) may be enhanced in Pb-Pb ALICE, PLB 734 (2014) 314

31. Comparing charmonia and open charm: Pb-Pb 31 0-10% R PbPb J/ = 0.56 ± 0.02 ± 0.02 ± 0.08  Forward rapidity: results for muons with p T >4 GeV/c  Extrapolation to all p T problematic ALICE, PLB 734 (2014) 314

32. J/ in Pb-Pb: run-1 summary 32  Evidence for smaller suppression compared to RHIC  Occurrence of recombination is at present the only explanation  p T -dependence of R PbPb also compatible with recombination  Although qualitative interpretation looks unambiguous, the quantitative assessment of the effects at play needs refinement  Values for d cc /dy evolved. At present, in the forw.-y ALICE domain:  SHM  0.15 – 0.25 mb (y=4 and y=2.5) – no shadowing  Zhao and Rapp  0.5 mb – “empirical” shad. vs no shad.  Zhuang et al.  0.4 – 0.5 mb – EKS98 shadowing  Ferreiro et al.  0.4 – 0.6 mb + Glauber-Gribov shad. ~ nDSG(min.) > EKS98  LHC run-2  (almost) a factor 2 gain in s  would it be possible to extract d cc /dy which gives the best fit to run-1 results, extrapolate to run-2 energy (FONLL?) and give predictions ?  Suppression persists up to the largest investigated p T  Higher p T reach in run-2  increase of R PbPb ? Predictions ?  Interesting indication for azimuthal anisotropies. Run-2 needs  Experiment  (much) larger statistics  Theory  solid predictions

33. J/ in p-Pb: run-1 summary 33  p-Pb data: characterization of CNM effects in terms of shadowing plus coherent energy loss (no break-up) looks satisfactory  Effects are strong, R pPb ~ 0.6 at low p T and central to forward rapidity  Strong influence of CNM effects in Pb-Pb in the corresponding kinematic region  Uncertainties on shadowing calculations are large, could one use the LHC data to better constrain shadowing ?  The simple estimate R PbPb CNM =R pPb R Pbp (inspired to a shadowing scenario) leads, once this effect is factorized out, to an even steeper p T -dependence of R PbPb  Also for p-Pb, run-2 energy predictions (s~8 TeV), with parameters TUNED on run-1 results, would allow a crucial test of our understanding of the involved mechanisms

34. 34 The (2S) yield is compared to the J/ one in Pb-Pb and in pp  Improved agreement between ALICE and CMS data (wrt preliminary) (2S)/J/ in Pb-Pb  CMS (central events) p T >3 GeV/c & 1.6<|y|<2.4  (2S) less suppressed than J/ p T >6.5 GeV/c & |y|<1.6  (2S) more suppressed than J/

35. 35 (2S) R pPb vs y cms  (2S) suppression is stronger than the J/ one and reaches a factor ~2 wrt pp  Same initial state CNM effects (shadowing and coherent energy loss) expected for both J/ and (2S) Theoretical predictions in disagreement with (2S) result Other mechanisms needed to explain (2S) behaviour?  Final state effects related to the (hadronic) medium created in the p-Pb collisions? N.B.: crossing times smaller than formation time, no nuclear break-up (Forward-y:  c ~10 -4 fm/c, backward-y:  c ~710 -2 fm/c) ALICE Coll., JHEP12(2014)073

36. 36 (2S) Q pPb vs event activity  The (2S) Q pA is evaluated as a function of the event activity  Rather similar (2S) suppression, increasing with N coll, for both ALICE and PHENIX results with Q pA instead of R pA due to potential bias from the centrality estimator, which are not related to nuclear effects

37. J/ and (2S) Q pPb vs event activity  J/ and (2S) Q pA are compared vs event activity  forward-y: J/ and (2S) show a similar decreasing pattern vs event activity  backward-y: the J/ and (2S) behaviour is different, with the (2S) significantly more suppressed for largest event activity classes  Another hint for (2S) suppression in the (hadronic) medium? 37

38. (2S): run-1 summary 38  In Pb-Pb collisions the CMS results show an enhancement of the (2S) yield, compared to J/, at intermediate p T, and a suppression at low p T  A convincing explanation of the Pb-Pb results is still lacking  The ALICE preliminary results are marginally compatible with this observation (large uncertainties, low S/B)  In p-Pb collisions a significant suppression, compared to J/, is observed  The effect becomes very strong at backward rapidity, and implies sizeable final-state effects on the (2S)  Formation-time vs crossing-time arguments imply that the suppression may be related to the (hadronic?) medium created in p-Pb collision  First theory calculations support this interpretation  Run-2 is expected to yield large luminosity, mandatory for a meaningful study of (2S) in Pb-Pb

39. 39  suppression in Pb-Pb collisions LHC is the machine for studying bottomonium in AA collisions Main features of bottomonium production wrt charmonia: no B hadron feed-down gluon shadowing effect are smaller (re)combination expected to be smaller theoretical predictions more robust due to the higher mass of b quark with a drawback…smaller production cross-section Clear suppression of  states in PbPb with respect to pp collisions CMS Coll., PRL 109, 222301 (2012) pp PbPb

40. 40  suppression in Pb-Pb collisions Strong suppression of (2S) (1S) suppression compatible with suppression of excited states (50% feed-down) Sequential suppression of the three  states according to their binding energy: Suppression at LHC is stronger than at RHIC R AA ((1S)) = 0.56 ± 0.08 (stat) ± 0.07 (syst) R AA ((2S)) = 0.12 ± 0.04 (stat) ± 0.02 (syst) R AA ((3S)) <0.1 (at 95% C.L) CMS Coll., PRL 109, 222301 (2012)

41. 41 Comparison of ALICE vs CMS results Stronger suppression at forward rapidity than at mid-rapidity, in particular for central collisions Comparison of ALICE (forward-y) and CMS (mid-y) results CMS Coll., PRL 109 (2012) 222301 ALICE Coll., PLB 738 (2014) 361 ALICE CMS ALICE CMS

42. 42 Comparison with theory Evolving QGP described via a dynamical model including suppression of bottomonium states, but not CNM nor recombination 2 different initial temperature y profiles: boost invariant or Gaussian (3 tested shear viscosity) MODEL The model underestimates the measured (1S) suppression at forward-y, while it is in fair agreement with mid-y data

43. 43 Comparison with theory Transport model accounting for both regeneration and suppression CNM effects included via an effective absorption cross section (0-2 mb) MODEL The measured R AA vs centrality is slightly overestimated by the model at forward-y, while it reproduces CMS results Constant R AA behavior vs y is not supported by the data

44. (1S) measured at forward-y by both ALICE and LHCb  Compatible R pA results within uncertainties (but LHCb systematically higher) Hint for stronger suppression at forward-y (similarly to J/) Theoretical calculations based on initial state effects seem not to describe simultaneously forward and backward y 44 ALICE Coll., PLB 740 (2015) 105-117 LHCb Coll., JHEP 07(2014)094 (1S) Production in p-Pb

45. 45 CMS Coll., JHEP 04 (2014) 103 CMS Coll., PRL 109 (2012) (2S)/(1S) (ALICE) 2.03<y<3.53: 0.27±0.08±0.04 -4.46<y<-2.96: 0.26±0.09±0.04 Compatible with pp results 0.26±0.08 (ALICE, pp@7TeV) Initial state effects similar for the three  states p-Pb vs pp @mid-y: final states effects in p-Pb affecting the excited states p-Pb vs PbPb @mid-y : even stronger suppression of excited states in PbPb ALICE (and LHCb) observes:CMS analyses the double ratio [(2S)/(1S)]/[(nS)/(1S)] pp and finds p-Pb Pb-Pb 0.83±0.05±0.05 (nS)/(1S) Production in p-Pb

46. 46 (nS)/(1S) vs event activity Strong decrease with increasing charged particle multiplicity both in pp and p-Pb  production affects multiplicity? or multiplicity affects the ? activity around the  breaks the state (1S) produced with more particles than excited states Weaker dependence when the activity estimator is in a different kinematic region with respect to the  CMS Coll., JHEP 04 (2014) 103

47. : run-1 summary 47  First detailed study of bottomonia in HI collisions  Suppression of 1S, 2S, 3S states clearly observed  More weakly bound states are more suppressed  Evidence for sequential suppression  Suppression of 1S state at mid-rapidity consistent with feed-down effects  Rapidity dependence of 1S suppression exhibits surprising features  Still not satisfactorily reproduced by models  p-Pb results, still significant uncertainties at forward-y, no sharp conclusions  At central rapidity, evidence for final-state effects on 2S and 3S states  CMS R pPb results still to be delivered  Intriguing features on yields vs event activity

48. Conclusions (1) 48  LHC run-1 has led to a very significant advance of our understanding of charmonia/bottomonia in hot matter  Charmonium highlight  evidence for a new mechanism which enhances the J/ yield, in particular at low p T, with respect to low-energy experiments  In addition  Indications for J/ azimuthal anisotropy (non-zero v 2 )  Significant final state effects on (2S) in p-Pb, likely related to the (hadronic) medium created in the collision  Bottomonium highlight  evidence for a stronger suppression of 2S and 3S states compared to 1S. Effect not related to CNM and compatible with sequential suppression of “bottomonium” states  In addition  1S is also suppressed (~50%). Feed-down effect only?  y-dependence of 1S suppression to be understood

49. Conclusions (2) 49  Prospects for run-2  Collect a ~1 order of magnitude larger integrated luminosity  High-statistics J/ sample  Comparison with run-1 AND with theoretical predictions crucial to confirm/quantify our understanding in terms of regeneration  Significant (2S) sample  Crucial: run-1 results “exploratory” (and interpretation not clear)  High-statistics (1S) sample  A significant increase in 1S suppression with respect to run-1 might imply that a high-T QGP is formed (“threshold” scenario)  Differential (2S) and (3S) results from run-1 are limited by statistics  Centrality and p T -dependent studies important to assess details of sequential suppression

50. Backup 50

51. 51

52. 52

53. 53

54. RHIC: suppression vs recombination  Did we reach a consensus on the role played by recombination at RHIC ? J/ p T distribution  should be softer ( ) wrt pp J/ elliptic flow  J/ should inherit the heavy quark flow One should in principle observe  Evidence not compelling  Could weaker suppression at y=0 be due to other effects (CNM, for example)?

55. CMS, focus on high p T  Muons need to overcome the magnetic field and energy loss in the absorber  Minimum total momentum p~3-5 GeV/c to reach the muon stations  Limits J/ acceptance  Midrapidity: p T >6.5 GeV/c  Forward rapidity: p T >3 GeV/c..but not the  one (p T > 0 everywhere)

56. Non-zero v 2 for J/ at the LHC 56 CMS HIN-2012-001 E.Abbas et al. (ALICE), PRL111(2013) 162301  The contribution of J/ from (re)combination should lead to a significant elliptic flow signal at LHC energy  A significant v 2 signal is observed by BOTH ALICE and CMS  The signal remains visible even in the region where the contribution of (re)generation should be negligible  Due to path length dependence of energy loss ? Expected for J/ ?  In contrast to these observations STAR measures v 2 =0

57. Finally, the  57  LHC is really the machine for studying bottomonium in AA collisions (and CMS the best suited experiment to do that!)

58. First accurate determination of  suppression 58  Suppression increases with centrality  First determination of (2S) R AA : already suppressed in peripheral collisions  (1S) (see also ALICE) compatible with only feed-down suppression ?  Probably yes, also taking into account the normalization uncertainty Compatible with STAR (1S+2S+3S)(but large uncorrelated errors): expected ? Is (1S) dissoc. threshold still beyond LHC reach ?  Full energy

59. (1S) vs y and p T from CMS+ALICE 59  Start to investigate the kinematic dependence of the suppression  Suppression concentrated at low p T (opposite than for J/, no recombination here!)  Suppression extends to large rapidity (puzzling y-dependence?)

60. Do not forget CNM… 60  Also in the  sector, the influence of CNM is not negligible  With respect to 1S, the 2S and 3S states are more suppressed than in pp… but less than in Pb-Pb  confirm Pb-Pb suppression as hot matter effect  As a function of event activity, loosely related to centrality in pPb (and surely not in pp!) “smooth” behaviour: to be understood!

61. RHIC: energy scan 61  System size and energy dependence of R AA  No appreciable dependence on both energy and system size  Not trivial! Requires  counterbalancing of suppression+regeneration effects over a large s-region (note however large global systematics)  Warning: CNM effects (shadowing) expected to vary with s

62. Quarkonia – where are we ? 62  Two main mechanisms at play 1)Suppression in a deconfined medium 2)Re-generation (for charmonium only!) at high s can qualitatively explain the main features of the results  ALICE is fully exploiting the physics potential in the charmonium sector (optimal coverage at low p T and reaching 8-10 GeV/c)  R AA  weak centrality dependence at all y, larger than at RHIC  Less suppression at low p T with respect to high p T  CNM effects non-negligible but cannot explain Pb-Pb observations  CMS is fully exploiting the physics potential in the bottomonium sector (excellent resolution, all p T coverage)  Clear ordering of the suppression of the three  states with their binding energy  as expected from sequential melting  (1S) suppression consistent with excited state suppression (50% feed-down)

63. Conclusions 63 LHC: first round of observations EXTREMELY fruitful  Many (most) of the heavy-quark/quarkonia related observables were investigated, no showstoppers, first physics extracted  Many (most) of the heavy-quark/quarkonia related observables would benefit from more data to sharpen the conclusions  full energy run, 2015-2017  upgrades, 2018 onwards RHIC: still a main actor, with upgraded detectors Lower energies: SPS, FAIR  Serious experimental challenge  High- B region of the phase diagram unexplored for what concerns heavy quark/quarkonia below 158 GeV/c

64. From R pA incl to R pA prompt 64  Assume R pA non-prompt = 1  The value of R pA prompt can differ significantly from R pA prompt at large f b

65. Is the difference significant for ALICE? 65  Exercise 1) Assume R pPb non-prompt =1 2) Plot R pPb prompt vs f b for the values of R pPb inclusive measured by ALICE 3) Plot the ALICE point at the f B value corresponding to the p T where the measurement is performed  Result For ALL the p T range accessible to ALICE, the difference between R pPb inclusive and the calculated R pPb prompt is smaller than the uncertainties

66. PHENIX – new systems/energies 66  Old system (Au-Au) at new energy: still a balancing of suppression and regeneration ?  Theory seems to say so….  New system (Cu-Au) at old energy: Cu-going finally different! (probably not a CNM effect)  A challenge to theory  SPS went the other way round (from S-U to Pb-Pb…)

67. PHENIX – CNM 67  First study of a charmonium excited state at collider energy  Seems contradicting our previous knowledge  p T dependence of R dAu  Increase vs p T at central/forward y  Reminds SPS observation  But different behaviour at backward rapidity  Not easy to reproduce in models! Overall picture still not clear !

68. STAR -  68  Bottomonium: the “clean” probe  3 states with very different binding energies  No complications from recombination But not that easy at RHIC! …and this has been split into 3 centrality bins…. Compatible with 3S melting and 2S partial melting

69. Hints from theory 69  Theory is on the data ! Fair agreement, but….  … one model has no CNM, no regeneration  …the other one has both CNM and regeneration (which would be responsible for all (2S) in central events) Still too early to claim a satisfactory understanding ?

70. 70 (2S) R pPb vs y cms  Can the stronger suppression of the weakly bound (2S) be due to break-up of the fully formed resonance in CNM? possible if formation time ( f ~0.05-0.15fm/c) < crossing time ( c ) forward-y:  c ~10 -4 fm/c backward-y:  c ~710 -2 fm/c break-up effects excluded at forward-y at backward-y, since  f ~ c, break-up in CNM can hardly explain the very strong difference between J/ and (2S) suppressions  Final state effects related to the (hadronic) medium created in the p-Pb collisions?  The (2S) suppression with respect to binary scaled pp yield can be quantified with the nuclear modification factor D. McGlinchey, A. Frawley and R.Vogt, PRC 87,054910 (2013) arXiv:1405.3796

71. Charmonia – data samples 71  ALICE  L int (2011) = ~70 b -1 (2.5<y<4), ~28 b -1 (|y|<0.9)  Trigger: MB + 2 tracks in the muon trigger chambers (p T > 1 GeV/c) Background subtraction via like-sign or mixed-event techniques B. Abelev et al., ALICE arXiv:1311.0214.

72. Charmonia – data samples 72 CMS PAS HIN-2012-014  CMS  L int (2011) = ~150 b -1 (|y|<2.4)  Trigger: dimuon events at L1 (no constraints on muon momentum) Use pseudo-proper decay length to estimate the b-hadron decay length N.B.: discuss only prompt production in this talk