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Prospects with Heavy Ions at the LHC

Prospects with Heavy Ions at the LHC. The Q u a r k - G l u o n Plasma at RHIC & LHC. So far at RHIC: Elliptic Flow  Near-perfect Fluid High p T Suppression  Strongly-coupled QGP Jet Quenching  Strongly-coupled QGP Away-side of jet  Energy dissipation/propagation in medium

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Prospects with Heavy Ions at the LHC

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  1. Prospects with Heavy Ions at the LHC John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  2. The Quark-Gluon Plasma at RHIC & LHC So far at RHIC: Elliptic Flow Near-perfect Fluid High pT Suppression Strongly-coupled QGP Jet Quenching Strongly-coupled QGP Away-side of jet Energy dissipation/propagation in medium Medium properties? Near-side Ridge Something new, unresolved Heating of the system Longitudinal expansion? Initial parton distributions? Initial parton bremsstrahlung + flow? ! !! !!! !!!! RHIC and LHC: Cover 2 – 3 decades of energy (sNN ~ 20 GeV – 5.5 TeV) What are the properties of hot QCD in this temperature range (T ~ 150 – 600 MeV)? John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  3. BIG Physics Questions for RHIC & LHC Heavy Ions • - How does the system evolve/decohere from its initial state? • - Initial state saturation / color glass? • - Rapid thermalization - how? - What are the properties & constituents (vs. T) of the QGP? • - e.g., screening length, bulk/shear viscosity, vs, diff. coeff.,…. • How do partons lose energy in the QGP? - How does the QGP respond to large energy deposition (“jet heating”) - Response of medium (e.g. away-side, near-side ridge)? - How does hadronization take place? John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  4. SPS RHIC LHC factor 28 5500 √sNN (GeV) 17 200 shorter 0.1 tform (fm/c) 1 0.2 3.0 - 4.2 hotter T / Tc 1.1 1.9 15-60 denser e(GeV/fm3) 3 5 > 10 longer-lived tQGP(fm/c) ≤ 2 2-4 Simple Expectations - Heavy Ion Physics at the LHC John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  5. Hard Scattering with Heavy Ion Physics at the LHC Significant increase in hard scattering yields at LHC: - jets & large pT processes - sbb (LHC ) ~ 100 sbb (RHIC) - scc (LHC) ~ 10 scc (RHIC) John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  6. How Will LHC Heavy Ions Contribute? - How does the system evolve/decohere from its initial state? - What are the properties & constituents (vs. T) of the QGP? - How do partons lose energy in the QGP? - How does the QGP respond to “jet heating” – response of medium (e.g. away-side, near-side ridge)? - How does hadronization take place? • - • - LHC extends reach to very low-x phenomena - • - LHC extends reach to higher T • - LHC extends abundance & diversity of probes • (e.g. flow of heavy quarks & quarkonia – v2 scaling?) • - • - LHC extends reach in mass, flavor, and pT of hard probes • (different parton probes, jets, Z-bosons, heavy quarks, quarkonia) - - Trigger on hard probes (above) of different mass, flavor and pT - - Investigate intermediate pT (5 – 15 GeV/c)hadron production - Investigate fragmentation process in detail (hadrochemistry in jets) - Investigate production of “new” scaler and vector particles John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  7. LHC Heavy Ion Collider Program • LHC to start s = 14 TeV p + p operation in Spring 2008 • LHC Heavy Ion operation • sNN = 5.5 TeV Pb + Pb • Anticipate 1 month per year • Detectors • ATLAS • CMS • ALICE John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  8. John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  9. ATLAS ATLAS – Multi-purpose, large acceptance system. Designed for large pT with extensive calorimetry for detailed jet studies. CMS– Multi-purpose, large acceptance system. Designed for large pT with calorimetry for detailed jet studies. CMS ALICE ALICE– Dedicated heavy ion experiment. Large suite of detectors for tracking and PID from 100 MeV/c to 100 GeV/c. Proposed calorimetry for jet trigger and studies. LHC Heavy Ion Collider Experiments John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  10. AdS/CFT (and all theories)MeetsHeavy Ions at the LHC John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  11. Prospects for AdS/CFT with LHC Heavy Ions LHC ions will investigate v2 for light & heavy particles (p,.…f, W,….B, D, J/y,…) PHENIX, PRL 98, 172301 (2007) From PHENIX non-g e-data, transport models require: • small heavy quark relaxation time • small diffusion coefficient DHQ x (2pT) ~ 4 – 6 constrain viscosity/entropy • h/s ~ (1.5 – 3) / 4p • within factor 2 - 3 of AdS/CFT conjectured lower bound* • consistent with light hadron v2 analysis * Kovtun, Son, Starinets, hep-th/0405231 John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  12. 15000 quarks flow collectively Baryons Mesons Prospects for AdS/CFT with LHC Heavy Ions What about the v2 “Quark Scaling” at intermediate pT ? My naïvete : how does this work? – Early flow & constituent quark scaling? John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  13. e E q ~ m ^ q = m2 / L Prospects for AdS/CFT with LHC Heavy Ions What is the dynamical origin of parton energy loss (quenching, suppression)? What happens to the radiation? Interference effects? Dist. relative to parton? How does parton lose energy? L What is dependence on mass, flavor and energy of parton? What about recoil energy of collisional E-loss? DEgluon > DEquark, m=0 > DEquark, m>0 One parameterization of energy loss  John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  14. Jets & High pT Particles with LHC Heavy Ions Jet Physics - Jets: measure parton E & E-loss, jet-tag (B vs. light quark, gluon) long. & transverse mod. of jet • g-jet, Z0-jet, di-jet: parton E & E-loss • Hadrochemistry in Jets fragmentation function mod. light flavored mesons – gluons parents D-mesons – quark parents (mc ~ 0) B-mesons – quark parents (mb > 0) John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  15. Eskola, Honkanen, Salgado, Wiedemann Nucl Phys A747 (2005) 511 q ~ m >100 GeV? ^ ^ q q = 5 – 15 GeV2 / fm from RHIC RAA Data LHC? RAA(pT )? Parameterization of Parton Energy Loss at RHIC L John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  16. AdS5/CFT – Parton Energy Loss Results & Future! from J. J. Friess, S. S. Gubser and G. Michalogiorgakis,arXiv:hep-th/0605292. Future for AdS/CFT: What is the velocity dependence of energy loss? What is the mass & flavor (q, g) dependence of energy loss? What is radiated from the partons? H. Liu, K. Rajagopal and U. A. Wiedemann, arXiv:hep-ph/0605178, recent PRL John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  17. Trigger jet Near-side ridge Trigger Jet (near-side) Near-side ridge 3 < pt,trigger < 4 GeV pt,assoc. > 2 GeV Au+Au 0-10% preliminary J. Putschke, STAR, QM 2006 A Near-side “Ridge” Appears at RHIC! Di-hadron correlations h Jets: scale with # of binary collisions Ridge: exists to highest pT (trig) correlated with jets But ridge spectra ~ same as medium ( ‘bulk-like’, seen for mesons/baryons) thermal spectra + flow origin?jet-heating?........ John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  18. Possible “Ridge” Mechanisms So Far References to proposed explanations so far: • Radiated gluons, broadened by • Longitudinal flow,Armesto et al, PRL 93 (2004) • Color magnetic fields,Majumder et al, hep-ph/0611035 • Medium heating + recombination,Chiu & Hwa, PRC72, 034903 • Radial flow + trigger particle bias,Voloshin, N.P. A749, 287, Shuryak nuc-th/07063531 • Initial parton scatter + Jet-medium interactions,C.Y. Wong, hep-ph/07072385 John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  19. hep-ph/0706.0368 v >> vs Response of the Medium in AdS/CFT hep-th/0706.4302 Questions for AdS/CFT: Dependence on mass, flavor and velocity? John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  20. cc and bb rates (ALICE PPR) system shadowing NN x-sect (mb) total multiplicity p + p, 14 TeV 11.2/0.5 1/1 0.16/0.007 Pb + Pb, 5.5 TeV (5%) 6.6 /0.2 0.65/0.85 115 /4.6 Heavy Flavors at the LHC RAA of D and B-mesons to large pT at LHC AdS/CFT – dE/dx of heavy quarks - S. Gubser, “Drag Force in AdS/CFT”, hep-ph0605182, hep-th/0612023. - Chesler & Yaffe, hep-th/07060368. - Horowitz & Gyulassy, nuc-th/07062336. - …. John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  21. U J/y U SPS regeneration? RHIC LHC U’ J/ Y suppression? Events/100 MeV Mmm Color Screening of the Medium? J/y and U Physics - Melting of quarkonium states: - initial T - suppression / regeneration - color screening of medium? John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  22. hep-ph/0607062 E. Caceres, M. Natsume, T. Okamura, hep-th/0607233 AdS/CFT & Color Screening of the Medium? John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  23. Medium Modification of Fragmentation from Jets jet direction z N. Borghini, U. Wiedemann hep-ph/0506218 # particles with low z increases # particles with high z deceases pThadron~2 GeV Fragmentation along jet axis: z = phadron / p parton Introduce  = ln(Ejet / phadron)~ ln (1/z): Black line = radiative E-loss Dashed line = flat Collisional E-loss? John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  24. Medium Modifications and Jet Hadrochemistry Sapeta & Wiedemann, hep-ph/07073894 Parton energy loss can alter: parton’s color charge (flavor, baryon # ?) JAA RAA in jet cone John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  25. Hadronization, Fragmentation, Medium Modification Bourrely & Soffer, hep-ph/0305070: Each flavor parton - contributes differently to fragmentation function. - loses different amounts of energy in medium. Study z = phadron/pjet Requires high pT identified particles Jets, Intra- & inter-jet particle correlations z z Fragmentation at lower z in jets Hadronization of lower pT particles from colored medium. Both impacted by medium properties Microscopic hadronization process? John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  26. The Quark-Gluon Plasma at the LHC At LHC: Is the QCD phase diagram feature-less at 1 – 4 Tc? What happens as we go up in T (e.g. coupling)? Are there new phenomena? What’s the range of theoretical validities (non-pQCD, pQCD, strings)? Measure/understand parton energy loss at the fundamental level Establish flavor (gluon and quark mass) dependence Use jets and/or photons to establish hard-scattered parton energy Jet modifications - longitudinal & transverse “heating” Medium response to jet-heating (near- and away-side) Measure/use open charm and beauty decays (also as jet-tags) cc and bb states (screening, suppression, enhancement?) Direct Photon Radiation? Developments in theory (lattice, hydro, parton E-loss, string theory…) “the next frontier!” John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  27. AdS/CFT Meets Heavy Ions at the LHC…… Summaryof Physics Questions for both What is: - the velocity dependence of energy loss? • the flavor (q, g) dependence of energy loss? • radiated from partons in energy loss? • the response of the medium? • the color screening of the medium? • the particle type dep. of viscosity (flow)? • the basis for quark scaling of v2 at inter. pT • hadronization mechanism? John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  28. The Beginning The End John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

  29. Thanks for Discussions / Contributions to This Presentation!! Miklos Gyulassy Dima Kharzeev Peter Jacobs Urs Wiedemann John Harris (Yale) AdS/CFT Strings Intersect Beams at Columbia, 26 Oct. 2007

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