The Future of Quark Matter at RHIC

1. The Future of Quark Matter at RHIC higher luminosity + detector upgrades → how does this new plasma work? Barbara Jacak Stony Brook

2. Compelling reasons for higher luminosity* * and upgrading STAR, PHENIX • Entirely new questions posed by RHIC • fast thermalization mechanism? • how low is the viscosity of the liquid? • response of the plasma to deposited energy? • what is the color screening length? • is the initial state a color glass condensate? • Early questions still outstanding • nature of phase transition? critical point? • equation of state of hot QCD matter? • do heavy quark bound states melt? • can dilepton observables provide evidence for chiral symmetry restoration? Barbara Jacak QM06

3. RHIC and the phase transition • lattice says: collisions at RHIC map interesting region Tinit ~ 300 MeV Tfinal ~ 100 MeV Recall per massless degree of freedom Barbara Jacak QM06

4. There is some space left! STAR PHENIX Barbara Jacak QM06

5. Full Barrel Time-of-Flight system Forward Meson Spectrometer Forward triple-GEM EEMC tracker STAR Upgrades DAQ and TPC-FEE upgrade Integrated Tracking Upgrade Forward silicon tracker HFT pixel detector Barrel silicon tracker Barbara Jacak QM06

6. STAR TPC performance fall 2006 review report • distortion effects from space charge in TPC successfully corrected (to level of 100-200 mm) • procedures to tackle event pileup demonstrated in p+p and Cu+Cu collisions • expected to be successful also at higher luminosities • new readout electronics part of DAQ upgrade Barbara Jacak QM06

7. NCC NCC HBD MPC MPC VTX & FVTX Upgraded PHENIX Acceptance EMCAL 0 f coverage 2p EMCAL -3 -2 -1 0 1 2 3 rapidity (i) p0 and direct g with combination of all electromagnetic calorimeters (ii) heavy flavor with precision vertex tracking with silicon detectors combine (i)&(ii) for jet tomography with g-jet (iii) low mass dilepton measurments with HBD + PHENIX central arms Barbara Jacak QM06

8. RHIC II • electron cooling • L x40 • low energy run • possible now • # steps increased by cooling • ~30% higher e with U+U • feasible with EBIS • higher v2 sensitivity • (if geometry controllable) • constrain hydro • central nose-on collisions • rare – aided by higher L Expected whole vertex minbias event rate [Hz] Barbara Jacak QM06 T. Roser, T. Satogata

9. Compelling reasons for higher luminosity* * and upgrading STAR, PHENIX • Entirely new questions posed by RHIC • fast thermalization mechanism? • how low is the viscosity of the liquid? • response of the plasma to deposited energy? • what is the color screening length? • is the initial state a color glass condensate? • Early questions still outstanding • nature of phase transition? critical point? • equation of state of hot QCD matter? • do heavy quark bound states melt? • can dilepton observables provide evidence for chiral symmetry restoration? Barbara Jacak QM06

10. non-photonic single electrons how to measure viscosity and EOS? radial, directed & elliptic flow mass dependence of flow ↔ EOS ideal QGP: p = e /3 resonance gas: p > e /3 multistrange hadrons W, X, f v2 separate late stage dissipation from early viscous effects D meson v2→ thermalization time compare to viscous 3D hydro alsofluctuations, g & g* precision science: scan system size & energy Barbara Jacak QM06

11. PHENIX SiVX, RHIC II Detector upgrades improve PID v2 PHENIX SiVX, RHIC I vertex detector → D, B meson flow identified W v2 with TOF barrel RHIC II allows energy scan Barbara Jacak QM06

12. urgently need theory homework! • how to solve relativistic viscous hydrodynamics? • both theory and phenomenology • implement in 3D and run for data comparison • charm & strangeness v2 to probe limitations of hydro • improve pT reach • viscosity: an average quantity • pick apart momentum transport by different particles? • but this cannot be at the expense of fundamental theory! • understand the initial state (CGC→ glasma→ plasma) • thermalization? observables of instabilities • pre-equilibrium matter dynamics (e.g. molecular dynamics) Barbara Jacak QM06

13. Preliminary high luminosity energy scan map energy loss and medium response as function of T, mB Barbara Jacak QM06

14. where is the QCD critical point? energy scan up to mB ~ 500 MeV electron cooling will make this faster & allow finer steps Barbara Jacak QM06

15. Compelling reasons for higher luminosity* • Entirely new questions posed by RHIC • fast thermalization mechanism? • how low is the viscosity of the liquid? • response of the plasma to deposited energy? • what is the color screening length? • is the initial state a color glass condensate? Barbara Jacak QM06

16. Need better statistics at high pT from J. Lajoie talk C. Loizides hep-ph/0608133v2 Barbara Jacak QM06

17. Transport and extracting parameters from data • transport in plasmas is driven by collisions • transport of particles → diffusion • transport of energy by particles → thermal conductivity • transport of momentum by particles → viscosity • transport of charge by particles → electrical conductivity • how is color charge transported? • need theory progress to make it precision science • transport in medium where coupling is not weak • can J.P. Blaizot do this with resummation???? • scattering of particles from color fields (coherent?) • precise calculation of collective excitation observables • precise calculation of parton splittings in expanding medium Barbara Jacak QM06

18. golden channel: g-jet probe medium: precision correlations w/ 1 GeV h h-2h: jet-jet at RHIC II: 5Kp0, 10K direct g (pT ≥ 20 GeV) 7Kg-h in PHENIX 80K 20 GeV g-h and 5K 10GeV g + 2h(≥4 GeV) in ±1 unit y Barbara Jacak QM06

19. but wait, this is LHC territory! • Is RHIC II still exciting? • Two basic regions: • hard-hard correlations to study energy loss • hard-soft(ish) correlations for medium response • look at annual yields of events Barbara Jacak QM06

20. events per year p0 suppression at RHIC & LHC W.Vogelsang NLO RHIC II L= 20nb-1 LHC: 5 weeks run NB: large g/p0 at RHIC improves direct g as probe! Barbara Jacak QM06

21. g-h-h events per year STAR & upgraded PHENIX Many 3 particle coincidence events! Maybe full jet reco too… Jet energies lower than LHC… Barbara Jacak QM06

22. but ~10 GeV is where the medium action is! STAR nucl-ex/0604018 pT trigger > 8 GeV/c energy loss studies by 20 GeV jets should be accessible Barbara Jacak QM06

23. Compelling reasons for higher luminosity* • Entirely new questions posed by RHIC • fast thermalization mechanism? • how low is the viscosity of the liquid? • response of the plasma to deposited energy? • what is the color screening length? • is the initial state a color glass condensate? • Early questions still outstanding • nature of phase transition? critical point? • equation of state of hot QCD matter? • do heavy quark bound states melt? Barbara Jacak QM06

24. Karsch, Kharzeev, Satz, hep-ph/0512239 40% of J/y from c and y’ decays they are screened but direct J/y not? screening length: onium spectroscopy Barbara Jacak QM06

25. STAR Prelim. p+p 200 GeV e+e- Minv how to do better? • improve precision of data • larger pT reach • extend measurement to heavier states • theory effort needed Barbara Jacak QM06

26. Annual yields at RHIC II & LHC from Tony Frawley RHIC Users mtg. at LHC: x10-50 s but 10% of L and 25% running time Barbara Jacak QM06

27. Long term RHIC facility strategy Barbara Jacak QM06

28. Compelling reasons for higher luminosity * could motivate new experiment • Entirely new questions posed by RHIC • fast thermalization mechanism? * • how low is the viscosity of the liquid? • response of the plasma to deposited energy? * • what is the color screening length? • is the initial state a color glass condensate? * • Early questions still outstanding • nature of phase transition? critical point? • equation of state of hot QCD matter? • do heavy quark bound states melt? • can dilepton observables provide evidence for chiral symmetry restoration? Barbara Jacak QM06

29. backup slides Barbara Jacak QM06

30. Relevance to Heavy Ion Collisions from B. Zajc DNP • Collisions at RHICefficiently translate initial gluon state • Strong shadowing? • Saturated gluons? • Color Glass Condensate? • to final thermal state • Difficult to understand this efficiency without invoking some form of dense gluonic initial state • We would rather measure than invoke Barbara Jacak QM06 • An electron-Ion collider

31. RHIC II will get us • from “oh wow!” • we have found a surprising new form of matter • to “aha!” • here is how it works • how QGP relates to and helps progress in other fields Barbara Jacak QM06

32. A method to extract viscosity • Paul Stankus viscosity is a dissipative effect drive local equilibrium towards global equilibrium. So higher viscosity means lower v2, and also lower v3, v4, etc. (v1 is a special case, since it obeys a sum rule). v3 v2 • Colliding asymmetric systems will allow us access to odd values of vn • Is v3 more sensitive than v2 to viscosity? • Need A+B running with statistics comparable to Run4/5 • Takes advantage of RHIC flexibility & luminosity (feasible at LHC?) • Currently work on 3-D hydro and hydro+viscosity • Need to combine Hydro with cascade with Reco Barbara Jacak QM06

33. RHIC Heavy Ion Collisions Expected whole vertex minbias event rate [Hz] T. Roser, T. Satogata Dileptons & chiral symmetry restoration? • Search for critical point  bulk hadron production and fluctuations • Requires moderate luminosity • do-able in next few years? • Chiral symmetry restoration  dilepton production • Requires upgraded luminosity • With electron cooling: • 4 weeks run, 25% recording eff. electron trigger • √s = 20 GeV  109 events • 2 GeV 107 events • CERES ~ 4x107, • NA60 sampled ~ 1010 In+In Increase by factor 100 with electron cooling Barbara Jacak QM06

34. need to measure T directly! • Temperature via blackbody radiation • real & virtual g • as a function of e, m • e+e- also signal any late stage medium modification of hadrons huge backgrounds below 1.5 GeV mass or Eg detector upgrades to reject decays & measure charm Barbara Jacak QM06

35. Plasma properties we will measure at RHIC II Barbara Jacak QM06

36. to explore at RHIC II ≥ 2014 Barbara Jacak QM06

37. role of B decays in electron RAAandv2 ? • need RHIC II luminosity & deterctor upgrades • direct probe of extent & timescale of thermalization? • RHIC II will yield • statistics for v2, pT reach for heavy quarks • allow scan of systems with exclusive decay channels • relative abundance of charmed hadron states inner trackers for PHENIX and STAR Barbara Jacak QM06

38. use this technique to measure viscosity melt crystal with laser light induce a shear flow (laminar) image the dust to get velocity study: spatial profiles vx(y) moments, fluctuations → T(x,y) curvature of velocity profile → drag forces viscous transport of drag in  direction from laser compare to viscous hydro. extract h/r shear viscosity/mass density PE vs. KE competition governs coupling & phase of matter Csernai,Kapusta,McLerran nucl-th/0604032 Barbara Jacak QM06

39. minimum h at phase boundary? seen in strongly coupled dusty plasma B. Liu and J. Goree, cond-mat/0502009 Csernai, Kapusta & McLerran nucl-th/0604032 minimum arises because kinetic part of h decreases with G & potential part increases; measure by density-density correlation Barbara Jacak QM06

40. shear generally a phenomenon in crystals but not liquids Barbara Jacak QM06

41. proton pion Temperature: hydro, eloss say 380-400 MeV nucl-ex/0410003 Hydro models: Teaney (w/ & w/o RQMD) Hirano (3d) Kolb Huovinen (w/& w/o QGP) Barbara Jacak QM06

42. Plasmas exhibit screening • Debye length: distance where influence of an individual charged particle is felt by the other particles in the plasma • charged particles arrange themselves so as to effectively shield any electrostatic fields within a distance lD • lD = e0kT • ------- • nee2 • Debye sphere = sphere with radius lD • number electrons inside Debye sphere is typically large • ND= N/VD= rVD VD= 4/3 plD3 1/2 in strongly coupled plasmas it’s  1 Barbara Jacak QM06

43. Debye screening in QCD: a tricky concept • in leading order QCD (O. Philipsen, hep-ph/0010327) • vv Barbara Jacak QM06

44. don’t give up! ask lattice QCD Karsch, et al. running coupling coupling drops off for r > 0.3 fm Barbara Jacak QM06

45. screening masses from gluon propagator Screening mass, mD, defines inverse length scale Inside this distance, an equilibrated plasma is sensitive to insertion of a static source Outside it’s not. Nakamura, Saito & Sakai, hep-lat/0311024 T dependence of electric & magnetic screening masses Quenched lattice study of gluon propagator figure shows: mD,m= 3Tc, mD,e= 6Tc at 2Tc lD ~ 0.4 & 0.2 fm magnetic screening mass is non-zero not very gauge-dependent, but DOES grow w/ lattice size (long range is important) Barbara Jacak QM06

46. Implications of lD ~ 0.3 fm • can use to estimate Coupling parameter, G • G = <PE>/<KE> but also G = 1/ND • for lD = 0.3fm and e = 15 GeV/fm3 • VD = 4/3 plD3 = 0.113 fm3 • ED = 1.7 GeV • to convert to number of particles, use gT or g2T • for T ~ 2Tc and g2 = 4 • get ND = 1.2 – 2.5  G ~ 1 • NB: for G ~ 1 • plasma is NOT fully screened – it’s strongly coupled! • affects interaction s! • other strongly coupled plasmas behave as liquids, even crystals for G≥ 150 • dusty plasmas, cold atoms+ions , warm dense matter Barbara Jacak QM06

47. plasma • ionized but macroscopically neutral • exhibit collective effects interactions among charges of multiple particles • spreads charge out into characteristic (Debye) length, lD • >1 particles inside this length, screen each other • “normal” plasmas: EM interaction • can vary r, T independently • photon p, e usually irrelevant • can be strongly or weakly coupled • QCD plasma • T determines all properties (heavy q mass sets new scale) • intrinsically strongly coupled for accessible T • quarks & gluons NOT asymptotically “free to roam” • …not your mother’s plasma… Barbara Jacak QM06

48. HQ Energy Loss and Flow nucl-ex/0611018 (submitted to Phys. Rev. Lett.) Radiative energy loss only fails to reproduce v2HF. Heavy quark transport model has reasonable agreement with both RAA and v2HF. Small relaxation time t or diffusion coefficient DHQinferred for charm. Talk: F. Kajihara (2.1.07) Barbara Jacak QM06