1. Helen Caines Yale University Soft Physics at the LHC - Catania - Sept. 2006 Questions for the LHC resulting from RHIC Strangeness Outline Chemistry Yields - Centrality dependence Flow (radial and v 2 ) Intermediate p T

2. Helen Caines Catania – Sept 2006 2 p-p data Not just a base line! Interesting results in their own right. Need to push for p-p at the same energy. m T scaling - not absolute Separate shape for baryons and mesons Not really going to discuss – see Rene’s talk STAR Preliminary p-p 200 GeV

3. Helen Caines Catania – Sept 2006 3 m T scaling and jets Using PYTHIA split events into gluon and quark jet Quark jet events show mass dependence Gluon jet events show baryon/meson splitting Gluon jet domination at RHIC? What happens at the LHC?

4. Helen Caines Catania – Sept 2006 4 Statistical model results ● , K,p ● , K,p, ,  T LQCD ~160-170MeV ● , K,p ● , K,p, ,  Including  is important for  s Close to chem. equilibrium ! Close to net-baryon free T ch flat with centrality How fast does LHC reach  s =1? STAR preliminary Au+Au at √s NN =200GeVand 62 GeV Using Kaneta model

5. Helen Caines Catania – Sept 2006 5 Expectations at the LHC energies T ch 125 - 170 MeV Calculations from Kraus et al., (Eq.) Rafelski et al., (Non Eq.) Statistical model predictions for LHC Measurable differences in predictions from the models  s 1-5

6. Helen Caines Catania – Sept 2006 6 Strangeness meets heavy flavour STAR Preliminary d-Au √s=200 GeV PYTHIA tells us: Statistical recombination tells us: A. Andronic et al. PLB 571 (2003) D s    (BR 3.6%) + Use a “resonance” analysis technique  K + K - Our total charm cross-section calc. could be affected After background subtraction Should be feasible at LHC – more charm

7. Helen Caines Catania – Sept 2006 7 Excitation function of central mid-rapidity yields Baryon yields ~flat Anti-baryon rise sharply dN/dy extrapolations at the LHC  :10~30  :3~6  :0.4~0.7

8. Helen Caines Catania – Sept 2006 8 Centrality dependence We can describe p-p and central Au-Au Can we understand the centrality evolution? Look at the particle enhancements. E(i) = Yield AA /Npart Yield pp /2 STAR Preliminary Solid – STAR Au-Au √s NN = 200 GeV Hollow - NA57 Pb-Pb √s NN = 17.3 GeV Even without p-p LHC can determine centrality dependence

9. Helen Caines Catania – Sept 2006 9 The canonical to grand canonical transition STAR Preliminary K. Redlich Correlation volume: V= (A NN ) ·V 0 A NN = N part /2 V 0 = 4/3  ·R 0 3 R 0 = 1.1 fm proton radius/ strong interactions T = 170 MeVT = 165 MeV Seems that T=170 MeV fits data best – but shape not correct Au-Au √s NN = 200 GeV

10. Helen Caines Catania – Sept 2006 10 Varying T and R Calculation for most central Au-Au data Correlation volume: V 0  R 0 3 R 0 ~ proton radius strong interactions K. Redlich Au-Au √s NN = 200 GeV SPS data indicated R = 1.1 fm Can get same E(i) with differing R and T combinations

11. Helen Caines Catania – Sept 2006 11 N part dependence STAR Preliminary K. Redlich Correlation volume: V= (A NN )  ·V 0 A NN = N part /2 V 0 = 4/3  ·R 0 3 R 0 = 1.2 fm proton radius/ strong interactions T = 165 MeV  = 1 T = 165 MeV  = 2/3 T = 165 MeV  = 1/3 Shape described if production volume not prop. N part Au-Au √s NN = 200 GeV

12. Helen Caines Catania – Sept 2006 12 PHOBOS: Phys. Rev. C70, 021902(R) (2004) More on flavour dependence of E(i) STAR Preliminary PHOBOS: measured E(ch) for 200 and 19.6 GeV Enhancement for all particles? Yes – not predicted by model Similar enhancement for one s hadrons Au-Au √s NN = 200 GeV

13. Helen Caines Catania – Sept 2006 13 Soft physics scalings with entropy (N ch ) PHOBOS White Paper: Nucl. Phys. A 757, 28 nucl-ex/0505014 Lisa et al. ≈ 400 MeV (RHIC) ≈ 390 MeV (SPS)  HBT radii from different systems and different energies scale with (dN ch /dη) 1/3 v 2 scaling within “low density limit” scaling when use  part These are all scalings over several orders of magnitude of √s Most central LHC: dN ch /d  ~1200

14. Helen Caines Catania – Sept 2006 14 Strangeness vs entropy No scaling between energies    But does become ~linear at higher dN ch /d  Solid – STAR Au-Au √s NN = 200 GeV Hollow - NA57 Pb-Pb √s NN = 17.3 GeV Most central LHC: dN ch /d  ~1200 dN  /dy = dN  /dy ~20-30 dN  /dy = dN  /dy ~4-6 dN  /dy = dN  /dy ~0.5-1

15. Helen Caines Catania – Sept 2006 15 Blast-wave Blast-Wave: hydro inspired parameterization: –Parameter T kin –Parameter –Direct fit (  2 ) on the data Blast-Wave gives slightly different results for multi-strange At 62 GeV lower ~ 90 MeV ~ 160 MeV ~ 125 MeV NA57 : C. Alt et al. Phys. Rev. Lett 94 (2005) 192301 E. Schnedermann et al., Phys. Rev. C 48 (1993) 2462 F. Retière and M. Lisa, Phys. Rev. C 70 (2004) 044907 Blast-Wave :

16. Helen Caines Catania – Sept 2006 16 Ideal hydrodynamics  -, K -, p Best agreement for : T dec = 100 MeV α = 0.02 fm -1 α ≠ 0 : importance of initial conditions  0 = 0.6 fm/c T dec = 165 MeV T dec = 100 MeV α : initial (at τ 0 ) transverse velocity : v T (r)=tanh(αr) Central Data P.F. Kolb, J. Sollfrank and U.Heinz, Phys. Rev. C 62 (2000) 054909 P.F. Kolb and R. Rapp, Phys. Rev. C 67 (2003) 044903 P.F. Kolb and U.Heinz, nucl-th/0305084 Starts to fail earlier (lower p T ) less re-scattering?

17. Helen Caines Catania – Sept 2006 17 T dec = 164 MeV T dec = 100 MeV Ω - spectra, central Ideal hydro and the  Both energies best reproduced with T dec ≈100 MeV (as  -, K -, p) T dec ≈ 164 MeV (T ch ) :Not enough flow P.F. Kolb and U. Heinz, nucl-th/0305084 If not same physical quantity stick to hydro. Need better models (hydro+hadronic phase) B-W fit on hydro : T kin ≠ T dec (up to 30 MeV difference) Au-Au 200 GeV

18. Helen Caines Catania – Sept 2006 18 v 2 of strange hadrons All strange particles flow - s quark flow same as light quark Indication for collective flow in partonic phase (small hadronic x-section for Ω, φ) Baryon “remembers” it was incoming STAR Preliminary

19. Helen Caines Catania – Sept 2006 19 Constituent quark scaling of v 2 STAR Preliminary Au-Au 62 GeV High statistics data show idealized scaling fails at 200 GeV See scaling at 62 GeV Where at LHC (if at all) will hydro/reco switch occur? PHENIX (open symbols) PRL 91 182301 (2003) v 2 saturates for p T > 3 GeV/c Clear baryon/meson difference at intermediate to high p T

20. Helen Caines Catania – Sept 2006 20 √s NN =62 GeV 0-5% 40-60% Nuclear modification factors - R CP √s NN =200 GeV 0-5% 40-60% NA57 nucl-ex/0507012 √s NN =17.3 GeV 0-5/40-55% Recombination or different “Cronin” for  and K at SPS? Differences between  and   B absorption?

21. Helen Caines Catania – Sept 2006 21 R cp vs Energy STAR Preliminary NA57: G. Bruno, A. Dainese: nucl-ex/0511020 The top SPS and top RHIC energy data are consistent 62 GeV Au+Au data also follows the same trend Is coalescence present in all systems? Does same pattern exist at LHC and out to higher p T ?

22. Helen Caines Catania – Sept 2006 22 Summary Stat. models predict little change in strangeness at LHC unless over-saturation occurs What about charm? Transition of strangeness from p-p to A-A not well understood No N part scaling Several soft sector variables scale with dN ch /d  (i.e. entropy) HBT, v 2 at low densities, strangeness centrality dependence Hydro does not need early multi-strange freeze-out Need more complex models v 2 of s quarks same as for light quarks Baryons retain “memory” of beam? Reco. traits observed at all energies – v 2, R cp New & detailed results from RHIC but as many new soft physics questions remain for LHC as have been answered

23. Helen Caines Catania – Sept 2006 23 Comparison between p-p and Au-Au T171 ± 9 MeV ss 0.53 ± 0.04 r3.49 ± 0.97 fm Canonical ensemble T168 ± 6 MeV ss 0.92 ± 0.06 r15 ± 10 fm Au-Au √s NN = 200 GeV STAR Preliminary p-p √s = 200 GeV STAR Preliminary

24. Helen Caines Catania – Sept 2006 24 Recent ReCo Model Predictions Premise: Observable: STAR Preliminary The production of Φ and Ω particles is almost exclusively from thermal s quarks even out to 8 GeV/c The ratio of Ω/  yields should rise linearly with p T

25. Helen Caines Catania – Sept 2006 25 HBT radii Entropy determines radii No obvious trends as f n of √s  HBT radii from different systems and at different energies scale with (dN ch /dη) 1/3 power 1/3 gives approx. linear scale nucl-ex/0505014 Lisa et al. ≈ 400 MeV (RHIC) ≈ 390 MeV (SPS) Works for different m T ranges

26. Helen Caines Catania – Sept 2006 26 Eccentricity and low density limit At hydro. limit v 2 saturates At low density limit Apparent complete failure. Especially at low density! Voloshin, Poskanzer PLB 474 (2000) 27 v 2 different as f n N part and energy PHENIX preliminary

27. Helen Caines Catania – Sept 2006 27 Fluctuations matter Important for all Cu-Cu and peripheral Au-Au PHOBOS QM2005

28. Helen Caines Catania – Sept 2006 28 PHOBOS preliminary h ± 0-50% centrality v2v2 Elliptic flow PHENIX preliminary v 2 decreases by ~ 50% from RHIC to SPS PHENIX preliminary v 2 same for 200 – 62 GeV Au-Au at fixed p T v 2 same in Au-Au and Cu-Cu for same centrality No perfect scaling but hints

29. Helen Caines Catania – Sept 2006 29 N ch as measure of entropy Entropy in Heavy Ion > Entropy in p-p? J.Klay Thesis 2001 Different EOS? QGP?

30. Helen Caines Catania – Sept 2006 30 PHOBOS White Paper: Nucl. Phys. A 757, 28 1000 5.5 TeV 5 6 6.4 = RHICx1.6 Most central events: dN ch /d  ~1200 LHC prediction I

31. Helen Caines Catania – Sept 2006 31 LHC prediction II R o = R s = R l = 6 fm Most central events: dN ch /d  ~1200 dN ch /d   ~10.5

32. Helen Caines Catania – Sept 2006 32 LHC prediction III Most central events: dN ch /d  ~1200 S ~ 20 But I suspect I’m not in the low density limit any more so v 2 /  ~ 0.2

33. Helen Caines Catania – Sept 2006 33 62 GeV : Λ, Ξ central Backup Ideal Hydrodynamics

34. Helen Caines Catania – Sept 2006 34 Λ, Ξ centrality dependence Backup Ideal Hydrodynamics

35. Helen Caines Catania – Sept 2006 35 Compilation of comparisons Use π, K, p B-W parameters on multi- strange baryons –T kin = 90 - 100 MeV – = 0.57 c Ξ - and Ω - spectra not reproduced J. Speltz (for the STAR Collaboration), nucl-ex/0512037 Differences between Ξ -, Ω - and π, K, p mainly due to (best constrained) Backup

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39. Helen Caines Catania – Sept 2006 39 Chemistry in forwards direction BRAHMS PRELIMINARY  b drives the production ratios – Where does LHC sit? Differences appearing in p-p production

40. Helen Caines Catania – Sept 2006 40 Mid-rapidity net-proton yield 62.4 GeV: PHOBOS Preliminary 200 GeV: PHENIX PRC 69, 024904 (2004) (correlated errors assumed: underestimated errors) Net protons (p–p) yield proportional to N part (within errors!) Really “strange” result: Number of protons ‘transported’ to midrapidity per participant pair is independent of number of collisions per participant! PHOBOS Preliminary If net baryons remain at LHC need better description of how transport occurs

41. Helen Caines Catania – Sept 2006 41 THERMUS  B 45 ± 10 MeV  S 22 ± 7 MeV  Q -21 ± 8 MeV T168 ± 6 MeV ss 0.92 ± 0.06 SHARE  q 1.05 ± 0.05 (23 MeV) ss 1.02 ± 0.08 (5 MeV) T133 ± 10 MeV ss 2.03 ± 0.6 qq 1.65 ± 0.5 ss 1.07 ± 0.2 Kaneta  B 8.0 ± 2.2 MeV  S -10.3 ± 4.5 MeV T154 ± 4 MeV ss 1.05 ± 7 0-5% Au-Au √s NN = 200 GeV All models not the same Statistical model calculations STAR Preliminary