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Future measurements in jet tomography at RHIC energies

Future measurements in jet tomography at RHIC energies. Jiangyong Jia. Single particle as probe Jet correlation as probe. Thank Takao, Zhangbu Xu for providing useful input. Interaction between jet and Medium. Peripheral Collision. Central Collision. Handles of Jet tomography.

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Future measurements in jet tomography at RHIC energies

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  1. Future measurements in jet tomography at RHIC energies Jiangyong Jia Single particle as probe Jet correlation as probe Thank Takao, Zhangbu Xu for providing useful input Workshop on Future Prospects in QCD at High Energy

  2. Interaction between jet and Medium Peripheral Collision Central Collision Jiangyong Jia

  3. Handles of Jet tomography • Single particle spectra • PID spectra out to high pT (p0±, h, k, p,L) * • Direct photon. * • Heavy flavor to high pT (NP-electron, Dkp) ** • Jets • 2-particle correlation in Df and Dh * • g – h correlation. * • Identified – identified correlation * • Heavy flavor – hadron correlation (e-h, D-h). * • Multi-particle correlation * • Full jet reconstruction (g-jet, HQ-jet) * • Variables to explore • pT, centrality and h dependence. • Reaction Plane dependence (or v2 in single particle case) • Species dependence (Cu+Cu, Au+Au, U+U, A+B). • Energy dependence (sps energy  200 GeV) • Reference p+p, p+A * Precision measurement * Exploratory measurement Jiangyong Jia

  4. Upgrades (STAR) J. Dunlop 2005 • Barrel Time of Flight (TOF): Particle ID (e, hadrons) • Current prototype patches to be upgraded to full azimuth, -1 < h < 1. • Project is funded and proceeding • Heavy Flavor Tracker (HFT): Displaced vertices • High precision (<10 um) measurements for displaced vertices • Goal: standalone detector in place for RHIC run in 2009 • Barrel Electromagnetic Calorimeter (EMC): High pt (e,g) • ¾ barrel of run 5 has been instrumented to full azimuthal coverage, -1 < h < 1, for next RHIC run: COMPLETE • Forward Meson Spectrometer (FMS): Low x physics • Full azimuthal EM Calorimetry 2.5 < h < 4.0 • Possibility of charm measurements in this region • Project is proceeding: complete by next d+Au run • Data acquisition upgrade (DAQ1000): Data rate 10x • Upgrade TPC readout an order of magnitude, ~double effective Luminosity • Target for completion: RHIC run in 2008 Large coverage, and fantastic PID, Heavy flavor capabilities and high DAQ rate Existing detectors will gain hugely from DAQ upgrade and RHIC II luminosity : TPC and Barrel EMC. Jiangyong Jia

  5. Upgrades (PHENIX) NCC NCC RxNP (2006-2009) MPC MPC VTX & FVTX • New large h coverage with NCC/MPC for p0, direct g and RP. • silicon detectors provide precision vtx tracking for Heavy favor. • Temporary RxNP detector for good RP measurement. • Extended pT for p0 and direct g with EMCal • Extended pT reach for p, k, p with RICH/AEROGEL. Central arm 0 f coverage 2p Central arm -3 -2 -1 0 1 2 3 rapidity Jiangyong Jia

  6. Upgrades and RHIC-II Near term RHIC-II RUN7 • RHICII 20 – 40 times gain in recorded luminosity • But we should continue making discoveries in next few years • PHENIX can have x10 RUN4 AuAu stat. in 25 weeks running and x10 RUN3 dAu stat. in 10 weeks running. • Besides some upgrades will be completed. • We can do low energy/species scan. Jiangyong Jia

  7. Single particle suppression • Calibrated probe: pQCD + factorization theorem • Experiment measurement well controlled Jiangyong Jia

  8. High pT v2 approach the radiative eloss limit AMY PQM v2 come from pQCD jets? Jiangyong Jia

  9. Theoretic descriptions • pQCD  initial geometry + jet quenching  dynamic geometry • RAA depends on both TAB andp(DE). • Many types of p(DE) can be tuned to match data. T. Renk hep-ph/0607166 All leads to surface emission but the details are different Hide behind the data error bar. Jiangyong Jia

  10. Centrality dependence • Two very different eloss models give equally good description • P(DE) = d(DE/E – f) – shift in pT • P(DE) = p0 d(DE)+(1-p0) d(DE-E) – shift down in yield. Centrality dependence has little constrain on energy loss model? A.Drees, H.Feng and J.Jia,Phys.Rev.C71:034909,2005 PHENIX White paper More complicated energy loss of X.N.Wang, I. Vitev, PQM, etc gives the same results. Jiangyong Jia

  11. qhat puzzle E>5 GeV/c DE/E DE/E E 5-14 GeV2/fm (Wiedemann/Salgado), 0.35-0.85 GeV2/fm (GLV), 2 GeV2/fm (AMY), few GeV2/fm (X.N. Wang/Majumder) • Models are tuned to match the central data, leading to different average qhat (<DE/E>) • Should compare directly p(DE)? Note: ADS/CFT 3-15 GeV2/fm, hep-ph/0605178 (factor of 3 smaller according to hep-ph0605158) • qhat  <DE>, however RAA depends not just on the average (<DE/E>) and but the actual distribution! (p(DE,r)) A model with smaller <DE/E> but narrower p(DE) width could lead to larger suppression!! (nucl-th/0512076) Jiangyong Jia

  12. Future measurements on hadron spectra • Precision measurement of the direct g production at intermediate and high pT. • Crucial input for g-jet analysis • Study various medium induced direct g , they do not scale with Ncoll. Turbide et.al PRL 96 032303 (2006) • Precision measurements of p0,k,p (L) at higher pT • Constrain different eloss models, and within same model, the qhat. • PID at high pT probe gluon/quark eloss & suppress the recombination effect Estimate with x8 statistics for PHENIX byT. Sakaguchi Jiangyong Jia

  13. Gluon vs. quark jet Log10(dE/dx) Hadron identification: STAR Collaboration, nucl-ex/0309012 Log10(p) STAR: nucl-ex/0606003 • Hint of deviation from eloss prediction • High statistic pp, dAu, AuAu and higher reach in pT are desirable pbar: gluon jets p: gluon/quark jets, pT dependent • STAR TOF & TPC  0.5-15 GeV/c for p, p separation • L, Ks out to very high pT via topological decay Jiangyong Jia

  14. Future measurement on hadron V2 • Precision measurements on the hadron and direct g v2 • Where is the end of recombination region (quark number scaling breaking?) • Will the v2 consistent with energy loss at highest pT? (constant?) RxNP • PHENIX RxNP detector greatly improve the RP resolution, by almost factor of 2 BBC Jiangyong Jia

  15. Future measurements on direct g v2 Brems and conversion g v2 Thermal g v2 Turbide et.al PRL 96 032303 (2006) R. Chatterjee et.al PRL.96:202302,2006 • Difference sources g have different v2 • Primary v2=0, thermal v2>0, fragmentation v2>0, brem and conversion v2<0 Jiangyong Jia (T. Sakaguchi)

  16. Heavy quark eloss • Surprisingly similar suppression level of electron as light mesons. • Radiative Eloss (before 2005) + Elastic Eloss (Mustafa, wicks et.al, Djordjevic) + multi-body interaction. • All with similar magnitude • Importance of multi-body interaction break down of pQCD in sQGP? • Elastic are important for light mesons! Nucl-th/0512076 C.M. Ko, HardProbe 2006 Jiangyong Jia

  17. Heavy quark flow Hendrik, Greco, Rapp nucl-th/0508055 w.o. B meson (c flow) w. B meson (c,b flow) • Non-photonic electron flow indicate strong medium interaction. • Competing mechanisms: Energy loss vs. Recombination • If RAA same as pion v2 is the same as p at high pT ? • Intermediate pT  will the D, B meson follow quark number scaling? ? Jiangyong Jia

  18. Future improvements • Charm and bottom quarks : DIFFERENT PDFs, cold nuclear effects, fragmentation/recombination and eloss pattern. • Complicates the physical interpretation of spectra and v2. • Separate c and b via displaced vtx STAR HFT, PHENIX VTX upgrade. • Reach higher pT with the increased statistics from RHIC II. S. Wicks, WH, M. Gyulassy, and M. Djordjevic, nucl-th/0512076 Large uncertainty on crossing point Jiangyong Jia

  19. VTX : statistically separate D/B PHENIX PHENIX RUN4 RUN2 • Displaced vertex tagging or hadronic decay: spectra and v2 • High stat. NP-decay electron measurement, focus on high pT • Can reduce the photonic contribution with silicon detectors • High pT: increase signal/bg, dominated by b quarks D v2 is possible, need 70-140M STAR Jiangyong Jia

  20. A confluent of away-side jet information low pT Intermediate pT nucl-ex/0507004 pT,assoc 0.2 GeV/c STAR Phys.Rev.Lett.95,2005 high pT Moderate high pT nucl-ex/0604018 4-6 x 2-4 GeV/c STAR STAR Phys. Rev. Lett. 90, (2003) What is the picture? Jiangyong Jia

  21. What is the picture? Low pT Intermediate pT Moderate high pT high pT Interplay between jet quenching, medium response and surviving jets!? Theory: Need quantitative and unified description Experiment :Need systematic/precision measurement merging or punchthough? or Increase pt I II III IV Shock wave or cherenkov? Recombination, Jet brodening Thermallized gluon radiation Punch through jets or tangential contribution? Away jet IAA 3T T Trigger and associated pT Jiangyong Jia

  22. Mach shock: No, Yes, Yes, maybe? • U. Heinz, nucl-th/0503028 Mach cone but not necessarily Mach peaks • J. Casalderrey-Solana hep-ph/0602183, depends on how one model jet core which can’t be treated hydrodynamically. No unique solution to hydro equation • G. Ma et.al. nucl-th/0601012, AMPT model (parton cascade s= 10mb) shows Mach peaks. • ADS/CFT: hep-th/0605292, hep-th/0606266 how well can one relate hard process in SYM with QCD? Jiangyong Jia

  23. Di-jets at high pT Punch through Tangential emission T. Renk 8 < pT(trig) < 15 GeV/c pT(assoc)>6 GeV, nucl-ex/0604018 Au+Au 0-5% Au+Au 20-40% d+Au STAR Near side jet yield is constant with centrality. Clear away side peak but increasing surpressed Jiangyong Jia

  24. Challenges of jet correlation measurement • Control background subtraction • Underlying event level : x. – mostly use ZYAM approach • What v2 value to use? – non flow effects etc. • Two source model assumption : <v2tv2a>=? <v2t><v2a> • Trigger bias. • Bias is more complicated than single particle. hard to constrain models (per-trigger-yield may not be a clean variable). CF = J(Df) + x(1+2v2tv2a cos2Df) Leading dijets T. Renk HP2006 Jiangyong Jia

  25. Thus direct g-jet as probe • Clear sensitivity using g-jet correlation • No suppression of leading g, IAA = RAA=0.2!! RAA IAA of direct g T. Renk hep-ph/0607166 • Suppression is on the PAIRS! • A simple case : type a has contribution from recombination, type b come only from jet. Then We know hadron IAA is close to RAA Jiangyong Jia

  26. Direct g-jet 5-10 x 3-5 GeV/c g-h p0-h 0-20% • No trigger bias. • Caveat: thermal, fragmentation, bremstrahlung, conversion g, depends on geometry not Ncoll • Clean tagging of g is difficult in AuAu • Rely on statistical subtraction of g-h and p0-h correlations. • Sensitive to ratio • pp, dAu measurement difficult: Jiangyong Jia

  27. Future expectation Case study for PHENIX • Current direct g-h correlation signal is marginal • Need go higher pT and expand acceptance • Au+Au statistics and upgrades (NCC/VTX) are crucial. • STAR will have more stats. But need improve the ability to distinguish decay and prompt photon. • Ldt pp equivalent Ng(>5) Ng(>6) Ng(>7) Ng(>8) Ng(>10) • Run4 AuAu 241mb-1 10pb-1 16k 5.5k 2.2k 1.2k 345 • Run5 CuCu 3nb-1 12pb-1 19k 6.6k 2.6k 1.4k 414 • Run5/6 pp 15pb-1 15pb-1 24k 8.3k 3.3k 1.7k 0.5k • RHIC-II x20 200pb-1 320k 110k 44k 24k 7k Jiangyong Jia

  28. Reaction plane dependence of jet correlation • PHENIX RxNP/NCC, STAR many detectors • can provides excellent RP measurement • Have to deal with the non-flow effect D. Winter, WWND2006 RxNP STAR, PRL 93 (2004) 252301 J. Bielcikova et al, PRC69:021901, 2004 • v2 varies in a predictable way • Can use it to constrain flow background subtraction! • Since near side modification is small at high pT, one can use it to constrain the path length dependence of away side suppression. Jiangyong Jia

  29. Three particle correlation: Bending or Mach Cone? Au+Au 0-10% Trigger Δ13 Δ12 Δ13 Df = 0 Cent=0-5% p1 Δ12 p2 p3 PHENIX Preliminary away – deflected = -0.04 ± 0.06 (stat) ± 0.09 (syst) away – cone = 0.13± 0.06 (stat) ± 0.05 (syst) More statistics is needed! New kinematical region: trigger on dijets (2 high pT particles) correlate with the third Jiangyong Jia

  30. Dh correlation and “Ridge” observation d+Au, 40-100% 3 —10 x 0.2 — 2 GeV/c Correlation with large Dh gap (|htrig|<1, 2.7<|hassoc|<3.9) • Near side ridge is consistent with zero • Broad away-side correlation, away side parton swing effect Au+Au, 0-5% F.Q. Wang HardProbe 2006 dN/dDf 3 < pT(trig) < 6 GeV2 < pT(assoc) < pT(trig) minbias Df hep-ph/0411341 Armesto,Salgado,Wiedemann Systematic study of Dh dependence (STAR/PHENIX upgrade) Jiangyong Jia

  31. Ridge characteristics pt,assoc. > 2 GeV Assoc. Protons Assoc. Pions Assoc. h preliminary Au+Au 0-10% J. Putschke HardProbe 2006 • Particles in the ridge has similar Df shape • Ridge yields are similar to inclusive single particle: • similar slope, large p/p ratio. Puzzling Results. • Control of the background subtraction is important. • Future PID Dh jet correlations help to clarify the picture STAR Jiangyong Jia

  32. PID correlation Fully Identified Jet Functions p/p ratio in the jet hadron – Meson vs. hadron –Baryon PHENIX Preliminary • Particle composition in the jet modified by medium? • Qualitatively described by recombination, • (R. Fries.PRL.94:122301) but what about the shape? Away side jet shapes are similar • Competing physics make the interpretation difficult. • Lacking systematical study in broader kinematical region. • Both STAR and PHENIX can extend the measurement to large pT. We can learn more together with PID spectra measurement. Jiangyong Jia

  33. Baseline understanding in d+Au • Low x physics (CGC) in forward region via spectra and correlation • Cold nuclear energy loss via p0 (PHENX), PID (STAR) • xg(x) via direct g (PHENIX EMCal/NCC) via p0p0+X (STAR FMS) STAR PHENIX PHENIX Mid-forward correlation p0 RdA at h=0 Direct g RdA at h=0 Jiangyong Jia

  34. Other Possibilities STAR • Heavy flavor correlation (D-h, e-h) • e-h correlation constrains charm and bottom contributionX. Lin hep-ph/0602067 • Energy scan to study the onset of jet quenching • Single spectra, jet correlation • Note: many competing mechanisms are as important! • Species scan to explore different geometry • Asymmetric system Cu+Au etc, very different path L dependence. v2n+1>0, test quark number scaling and jet quenching. • U+U collisions, achieve maximum eccentricity and energy density, maximum sensitivity to path L dependence. U. Heinz, PRL94:132301,2005 CERES Jiangyong Jia

  35. Handles of Jet tomography • Single particle spectra • PID spectra out to high pT (p0±, h, k, p,L) * • Direct photon. * • Heavy flavor to high pT (NP-electron, Dkp) ** • Jets • 2-particle correlation in Df and Dh * • g – h correlation. * • Identified – identified correlation * • Heavy flavor – hadron correlation (e-h, D-h). * • Multi-particle correlation * • Full jet reconstruction (g-jet, HQ-jet) * • Variables to explore • pT, centrality and h dependence. • Reaction Plane dependence (or v2 in single particle case) • Species dependence (Cu+Cu, Au+Au, U+U, A+B). • Energy dependence (sps energy  200 GeV) • Reference p+p, p+A * Precision measurement * Exploratory measurement Jiangyong Jia

  36. THE END Jiangyong Jia

  37. Collisional is equal/more important than radiative? • Collisional has smaller <DE/E> than radiative, but what is important is the eloss distribution p(DE). • One should directly compare the RAA. • A model with smaller <DE/E> but narrower p(DE) with could lead to larger suppression Jiangyong Jia

  38. STAR: direct separation of c,b. • STAR: Dkp. • STAR: > factor 10 improvement in NPE via HFT. Jiangyong Jia

  39. Control of the background subtraction is important. RUN2 RUN4 D. Magestro, HP2004 Jiangyong Jia

  40. Does the away side jet disappear at moderately high pT? STAR 4-6 x 2-4 GeV/c Phys. Rev. Lett. 90, (2003) Phys. Rev. Lett. 95, 2005 or Tangential/punchthrough fraction are there? Jiangyong Jia

  41. x PHENIX preliminary • is fixed ! systematic errors fixed! (v4 not included). Path length dependence is small Jiangyong Jia

  42. Shape can be constrained by the RP dependence • Shoulder and dip seen in all bins. • Direct constrains • The dip is significant for bin 4 where the v2 systematic is small. Jiangyong Jia

  43. How does the medium respond to the jets? QCD Mach cone: cos(q)=cs/c J. Casalderrey-Solana hep-ph/0602183 T=200MeV 1-2 GeV/c x3 2-3 GeV/c x10, 3-4 GeV/c Other possible mechanisms: Cherenkov radiation, bending jet, Gluon radiation… 0-5% PHENIX preliminary 2.5-4 x 1-2 GeV/c Jiangyong Jia

  44. Two particle correlation with large Dh gap |htrig|<1, 2.7<|hassoc|<3.9 3<pTtrig<10 GeV/c, 0.2<pTassoc< 2 GeV/c bkgd subtracted dN/dDf minbias Df Near-side consistent with zero, No ridge within large error. Forward particles have large Pz, Pz = 2 GeV/c for pT = 0.2 GeV/c hard to generate from flow. Broad away-side correlation. Away side parton swing effect Jiangyong Jia

  45. PHENIX: Cu+Cu high pT Jet Correlations Di-jet signal persists even for the most head-on Cu+Cu collisions. May allow better determination of matter properties! Jiangyong Jia

  46. One of RHIC’s Strengths: Play With Geometry At RHIC we can turn quite a few “knobs” by varying the energy, species and making asymmetric collisions (Dave Morrison) Npart Ncoll eccentricity b(fm) Jiangyong Jia

  47. Upgrades (STAR) • Large coverage, and fantastic PID, Heavy flavor capabilities • Existing detectors will gain hugely from DAQ upgrade and RHIC II luminosity : TPC and Barrel EMC. Jiangyong Jia

  48. FPD p+p→p0+X STAR preliminary STAR preliminary Jiangyong Jia

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