Questions for the LHC resulting from RHIC Strangeness

1. Questions for the LHC resulting from RHIC Strangeness Outline • Chemistry • Yields - Centrality dependence • Flow (radial and v2) • Intermediate pT

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

3. Using PYTHIA split events into gluon and quark jet mT scaling and jets Quark jet events show mass dependence Gluon jet events show baryon/meson splitting Gluon jet domination at RHIC? What happens at the LHC?

4. Statistical model results Close to net-baryon free Tch flat with centrality ● p, K,p ● p, K,p ● p, K,p, L, X ● p, K,p, L, X Close to chem. equilibrium ! STAR preliminary Au+Au at √sNN=200GeV and 62 GeV TLQCD~160-170MeV TLQCD~160-170MeV Including L is important for gs Using Kaneta model How fast does LHC reach gs =1?

5. Statistical model predictions for LHC Measurable differences in predictions from the models Expectations at the LHC energies Tch 125 - 170 MeV Calculations from Kraus et al., (Eq.) Rafelski et al., (Non Eq.) gs 1-5

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

7. Excitation function of central mid-rapidity yields dN/dy extrapolations at the LHC L : 10~30 X : 3~6 W : 0.4~0.7 Baryon yields ~flat Anti-baryon rise sharply

8. Centrality dependence Solid – STAR Au-Au √sNN = 200 GeV Hollow - NA57 Pb-Pb √sNN = 17.3 GeV STAR Preliminary We can describe p-p and central Au-Au Can we understand the centrality evolution? Look at the particle enhancements. E(i) = YieldAA/Npart Yieldpp /2 Even without p-p LHC can determine centrality dependence

9. The canonical to grand canonical transition Correlation volume: V= (ANN)·V0 ANN = Npart/2 V0 = 4/3 p·R03 R0 = 1.1 fm proton radius/ strong interactions STAR Preliminary Au-Au √sNN = 200 GeV T = 170 MeV T = 165 MeV Seems that T=170 MeV fits data best – but shape not correct K. Redlich

10. Varying T and R Calculation for most central Au-Au data Correlation volume: V0  R03 R0 ~ proton radius strong interactions Au-Au √sNN = 200 GeV SPS data indicated R = 1.1 fm Can get same E(i) with differing R and T combinations K. Redlich

11. Npart dependence STAR Preliminary Correlation volume: V= (ANN)a·V0 ANN = Npart/2 V0 = 4/3 p·R03 R0 = 1.2 fm proton radius/ strong interactions Au-Au √sNN = 200 GeV T = 165 MeV a = 1/3 T = 165 MeV a = 1 T = 165 MeV a = 2/3 Shape described if production volume not prop. Npart K. Redlich

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

13. Soft physics scalings with entropy (Nch) <kT>≈ 400 MeV (RHIC)<kT>≈ 390 MeV (SPS) nucl-ex/0505014 Lisa et al. v2 scaling within “low density limit” scaling when use epart PHOBOS White Paper: Nucl. Phys. A 757, 28 p HBT radii from different systems and different energies scale with (dNch/dη)1/3 Most central LHC: dNch/dh ~1200 These are all scalings over several orders of magnitude of √s

14. Strangeness vs entropy dNL/dy = dNL/dy ~20-30 dNX/dy = dNX/dy ~4-6 dNW/dy = dNW/dy ~0.5-1 L W X Solid – STAR Au-Au √sNN = 200 GeV Hollow - NA57 Pb-Pb √sNN = 17.3 GeV No scaling between energies But does become ~linear at higher dNch/dh Most central LHC: dNch/dh ~1200

15. Blast-wave Blast-Wave : E. Schnedermann et al., Phys. Rev. C 48 (1993) 2462 F. Retière and M. Lisa, Phys. Rev. C 70 (2004) 044907 • Blast-Wave: hydro inspired parameterization: • Parameter Tkin • Parameter <βT> • Direct fit (c2) on the data • Blast-Wave gives slightly different results for multi-strange • At 62 GeV <βT> lower ~ 160 MeV ~ 125 MeV ~ 90 MeV NA57 : C. Alt et al. Phys. Rev. Lett 94 (2005) 192301

16. Ideal hydrodynamics p-, K-, p • Best agreement for : Tdec= 100 MeVα = 0.02 fm-1 α ≠ 0 : importance of initial conditions t0 = 0.6 fm/c Central Data Tdec = 165 MeV Tdec = 100 MeV α : initial (at τ0) transverse velocity : vT(r)=tanh(αr) Starts to fail earlier (lower pT) less re-scattering? 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

17. Both energies best reproduced with Tdec≈100 MeV (as p-, K-, p) Tdec ≈ 164 MeV (Tch) :Not enough flow Ideal hydro and the W Tdec = 164 MeV Tdec = 100 MeV Ω- spectra, central P.F. Kolb and U. Heinz, nucl-th/0305084 Au-Au 200 GeV • B-W fit on hydro : Tkin ≠ Tdec (up to 30 MeV difference) If not same physical quantity stick to hydro. Need better models (hydro+hadronic phase)

18. v2 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. Constituent quark scaling of v2 STAR Preliminary Au-Au 62 GeV Where at LHC (if at all) will hydro/reco switch occur? PHENIX (open symbols) PRL 91 182301 (2003) v2 saturates for pT > 3 GeV/c Clear baryon/meson difference at intermediate to high pT High statistics data show idealized scaling fails at 200 GeV See scaling at 62 GeV

20. Nuclear modification factors - RCP √sNN=62 GeV 0-5% 40-60% 0-5% 40-60% √sNN=17.3 GeV 0-5/40-55% NA57 nucl-ex/0507012 √sNN=200 GeV Recombination or different “Cronin” for L and K at SPS? Differences between L and L B absorption?

21. Rcp vs Energy 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? STAR Preliminary Does same pattern exist at LHC and out to higher pT?

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 Npart scaling • Several soft sector variables scale with dNch/dh (i.e. entropy) • HBT, v2 at low densities, strangeness centrality dependence • Hydro does not need early multi-strange freeze-out • Need more complex models • v2 of s quarks same as for light quarks • Baryons retain “memory” of beam? • Reco. traits observed at all energies – v2 , Rcp New & detailed results from RHIC but as many new soft physics questions remain for LHC as have been answered

23. Comparison between p-p and Au-Au Au-Au √sNN = 200 GeV STAR Preliminary p-p √s = 200 GeV STAR Preliminary Canonical ensemble

24. Recent ReCo Model Predictions STAR Preliminary Premise: The production of Φ and Ω particles is almost exclusively from thermal s quarks even out to 8 GeV/c Observable: The ratio of Ω/f yields should rise linearly with pT

25. HBT radii <kT>≈ 400 MeV (RHIC)<kT>≈ 390 MeV (SPS) nucl-ex/0505014 Lisa et al. No obvious trends as fn of √s p HBT radii from different systems and at different energies scale with (dNch/dη)1/3 power 1/3 gives approx. linear scale Works for different mT ranges Entropy determines radii

26. Eccentricity and low density limit PHENIX preliminary v2 different as fn Npart and energy • At hydro. limit v2 saturates • At low density limit Apparent complete failure. Especially at low density! Voloshin, Poskanzer PLB 474 (2000) 27

27. Fluctuations matter PHOBOS QM2005 Important for all Cu-Cu and peripheral Au-Au

28. Elliptic flow PHOBOS preliminary h± 0-50% centrality v2 PHENIX preliminary PHENIX preliminary v2 same for 200 – 62 GeV Au-Au at fixed pT v2 decreases by ~ 50% from RHIC to SPS No perfect scaling but hints v2 same in Au-Au and Cu-Cu for same centrality

29. Entropy in Heavy Ion > Entropy in p-p? Nch as measure of entropy J.Klay Thesis 2001 Different EOS? QGP?

30. LHC prediction I 6 5 5.5 TeV 1000 6.4 = RHICx1.6 Most central events: dNch/dh ~1200 PHOBOS White Paper: Nucl. Phys. A 757, 28

31. LHC prediction II Most central events: dNch/dh ~1200 dNch/dh1/3 ~10.5 Ro = Rs = Rl = 6 fm

32. LHC prediction III Most central events: dNch/dh ~1200 S ~ 20 But I suspect I’m not in the low density limit any more so v2/e ~ 0.2

33. 62 GeV: Λ , Ξ central Backup Ideal Hydrodynamics

34. Λ , Ξ centrality dependence Backup Ideal Hydrodynamics

35. Compilation of comparisons Backup • Use π, K, p B-W parameters onmulti-strange baryons • Tkin = 90 - 100 MeV • <βT> = 0.57 c • Ξ- and Ω- spectra not reproduced • Differences between Ξ-, Ω- and π, K, p mainly due to <βT> (best constrained) J. Speltz (for the STAR Collaboration), nucl-ex/0512037

39. Chemistry in forwards direction BRAHMS PRELIMINARY mb drives the production ratios – Where does LHC sit? Differences appearing in p-p production

40. Mid-rapidity net-proton yield • Net protons (p–p) yield proportional to Npart (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 62.4 GeV: PHOBOS Preliminary 200 GeV: PHENIX PRC 69, 024904 (2004) (correlated errors assumed: underestimated errors)

41. Statistical model calculations 0-5% Au-Au √sNN = 200 GeV All models not the same STAR Preliminary