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An overview of high-p T correlations at SPS and RHIC

An overview of high-p T correlations at SPS and RHIC. Mateusz P ł osko ń. p+W @  s = 19.4GeV. R AA at SPS and RHIC. Energy density at  s = 17.3 GeV:  0  3GeV/fm3. Nucl. Phys. A 783 (2007). C. Blume. d N g /d y = 400-600 + Cronin + shadowing

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An overview of high-p T correlations at SPS and RHIC

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  1. An overview of high-pT correlations at SPS and RHIC Mateusz Płoskoń

  2. p+W @ s = 19.4GeV RAA at SPS and RHIC Energy density at s = 17.3 GeV: 0  3GeV/fm3 Nucl. Phys. A 783 (2007) C. Blume dNg/dy = 400-600 + Cronin + shadowing I. Vitev and M. Gyulassy, PRL 89 (2002), 252301 SPS • Direct photons scale with Nbin • High-pT hadrons are suppressed • At SPS: Interplay between Cronin enhancement and possible • jet quenching effects High-pT at LHC

  3. near side parton 1 trigger 1 STAR, Phys Rev Lett 91, 072304 associate 1 away side 2 associate 2 parton 2 Azimuthal Correlations p+p In A+A collisions away-side structure modified due to interaction with the medium 4 < pt,trig < 6 GeV and pt,assoc > 2 GeV A+A Medium(?) High-pT at LHC

  4. Two-particle correlations at SPS

  5. CERES Spectrometer with the TPC 2 Silicon Drift (SiDC) detectors, 2 RICH detectors, TPC : Dp/p = ((2%)2 + (1% p (GeV/c)2)1/2 Acceptance: 8o < q < 15o (2.1 < h < 2.65), full azimuth Data set: 30 mln Pb+Au events (year 2000 run) Centrality selection: 5%, 5-10%, 10-20% most central High-pT at LHC

  6. Pioneering plots: 2-pion azimuthal correlation- pre-TPC CERES analysis Two-particle azimuthal correlations of pions with pT > 1.2 GeV/c - centrality dependent. 24.2 - 30.0 % 19.3 - 24.2 % Broadening of the away-side component with centrality CERES Collaboration, G. Agakichev, et al. Phys. Rev. Lett. 92 (2004) 032301 10.6 - 15.1 % 15.1 - 19.3 % 21 - 26 % 6.1 - 10.6 % < 6.1 9 - 13 % The full line - Gaussian fits to semi-hard components on top of elliptic flow modulated background (dashed line) J. Bielcikova, PhD thesis Prague/Heidelberg 2003 High-pT at LHC

  7. Azimuthal angular 2-particle correlations - the recipe • Procedure (PHENIX: nucl-ex/0507004): • Accumulate: YAB(Df)=fA-fB(A != B) • Accumulate: Ymixed(Df)=fA-fCmixed • Divide normalized yields: • 4. Assume: • 5. Fix (C0) and subtract the flow (ZeroYieldAtMinimum(*)) • 6. Normalize and extract J • - jet associated particles(pairs) per trigger NA – number of triggers NAB – pairs Assuming eAB=eAeB the trigger efficiency cancels out High-pT at LHC

  8. A note on the ZYAM condition JET-A JET-T JET-B different event SIMULATION A Monte Carlo example Lets generate: - a trigger jet atDf = 0 - scattered jet (left or right) atDf = p - on top of flow ZYAM condition may overestimate the background contribution in cases where the (di-)jet yields/widths overlap The di-jet yield is nowhere ZERO High-pT at LHC

  9. 2-particle correlations from Pb+Au at 158 GeV/c All charged particles with 1.0 < pTassoc < 2.5 < pTtrigg < 4.0 GeV/c Strongly modified away-side in near central collisions as compared to a (expected) Gaussian-like shape. Modifications centrality dependent. Flow (v2) from the reaction plane analysis: nucl-ex/0510057 and refs there High-pT at LHC

  10. STAR 200 GeV/c Trigger-associated charge selection All charged with 1.0 < pTassoc < 2.5 < pTtrigg < 4.0 GeV/c MP, Nucl. Phys. A 783 (2007) Indication (near-side) for charge ordering in the fragmentation process. “Reversed yields” on the away side – correlated (di-)fragmentations(?) – global-di-jet charge conservation(?). Normalized to the total number of triggers (no charge selection) High-pT at LHC

  11. local minimum ? Charge-charge correlations - unfolded CERES data: Pb+Au at 158 GeV/c s/sgeom = 0 - 5 % S. Kniege nucl-ex/0703008 Independent of the trigger yield is dominated by the positive particles (in the fragmentation constrained to the pT-associated range) – PYTHIA calculations indicate isospin effects – not observed at RHIC nor at LHC. High-pT at LHC

  12. Selected correlations at RHIC

  13. Jet spectra STAR preliminary Ridge spectra Yield (pt,assoc > pt,assoc,cut) Yield (pt,assoc > pt,assoc,cut) STAR preliminary inclusive inclusive pt,assoc,cut pt,assoc,cut Medium on the near side ? STAR preliminary 0-10% Au+Au 3 < pt,trigger < 4 GeV, pt,assoc. > 2 GeV • Radiated gluons, broadened by • Longitudinal flow, Armesto et al, PRL 93 (2004) • QCD magnetic fields, Majumder et al, hep-ph/0611035 • Anisotropic plasma, P. Romantschke, PRC,75014901 (2007) • Medium heating + recombinationChiu & Hwa, PRC72, 034903 • Radial flow + trigger bias S. Voloshin, nucl-th/0312065, Nucl. Phys. A749, 287 Unfortunately not accessible at SPS experiments due to limited h acceptance) High-pT at LHC

  14. Shape evolving with centrality PHENIX, QM05 and nucl-ex/0507004 Away-side pT evolution: Clear narrow peak: Punch through Flat: Jet quenching – melting Double-peak structure: Mach cones shock waves + more… Broad cosine-like structure: thermalized gluons + momentum conservation STAR, Phys Rev Lett 95, 152301 High-pT Yield per trigger pTtrigger>8 GeV/c STAR, nucl-ex/0604018 Low-pT Away-side at RHIC High-pT at LHC

  15. CERES Pb+Au at sqrt(s) = 17.32 GeV/c Au+Au at 62.4 GeV/c nucl-ex/0511048 nucl-ex/0511043 Similar pT at RHIC… and SPS 1.0 < pTassoc < 2.5 < pTtrigg < 4.0 GeV/c PHENIX Au+Au at sqrt(s) = 200 GeV/c PHENIX, nucl-ex/0507004 Similar away-side structure (AND) evolving with centrality… … similar mechanism(s) at work at RHIC and SPS? High-pT at LHC

  16. 0-5% 5-10% 0-5% 5-10% 10-20% ? ? T. Renk K.J. Eskola J. Ruppert QM´06 Possible scenarios for the origin of the modified away-side Punch-through Possible broadening Strongly non-Gaussian Modified shapes ? • Double peak structure arising from Mach cone shock waves: H. Stöcker, Nucl. Phys. A 750, 121 (2005), J. Casalderrey-Solana, E. V. Shuryak and D. Teaney, Nucl. Phys. A 774, 577-580 (2006). • Induced gluon radiation: • I. Vitev, Phys. Lett. B 630, 78 (2005). • Cherenkov-like radiation: • V. Koch, A. Majumder and X.-N. Wang, Phys. Rev. Lett. 96, 172302 (2006). • Medium-induced radiative energy loss: • A. D. Polosa, C. A. Salgado hep-ph/0607295 High-pT at LHC

  17. EoS with 1st order phase transition t = 0 fm/c Medium in the mixed phase t = 12.8 fm/c Hydrodynamical Study of Jet Energy Loss B. Betz, Talk at DPG 2007 betz@th.physik.uni-frankfurt.de Emission Angle of the Mach Cones cosθ = cs / vjet ~ 60 – 90 deg F. Wang, QM06 • vjet depends on the mass of the leading quarks • masseless QGP: cs ~ 0.57 θ = 1.0 rad • hadronic matter: cs ~ 0.3 θ = 1.3 rad • 1st order phase transition: cs ~ 0 θ = 1.5 rad High-pT at LHC

  18. Three-particle correlations

  19. Considering different scenarios with Monte Carlo Jets • Di-jet correlation function – generated jets: • exactly back-to-back • smeared away side (randomized deflection) • away side scattered either left or right • conical away side pattern • leading to a double peak structure within the same event Different mechanisms may lead to similar structures in 2-particle correlations. 3-particle correlations provide additional topology information. High-pT at LHC

  20. 3-particle correlations – studying the jet-jet correlations - an example case SIMULATION fA-fT vs fB-fT High-pT at LHC

  21. s/sgeom: 7% Trigger pt : (2.5-4.0) GeV/c Associate pt : (1.0-2.5) GeV/c b=1 (Ulery and Wang) No assumption N22-part=N3-part Measured 3-particle correlations – Preliminary results CERES data: Pb+Au at 158 GeV/c Raw correlation function Reconstructed signal Subtraction of two particle correlations ( soft*soft , hard*soft ) Similar to J. G. Ulery and F. Wang nucl-ex/0609016 High-pT at LHC

  22. s/sgeom: (0.0-5.0)% Trigger pt : (2.5-4.0) GeV/c Associate pt : (1.0-2.5) GeV/c Projection onto 2-part. Df: Error of the projection (3-part. correl.) not indicated (but >> 0) Possible topology Cone-like emission Measured 3-particle correlations – Preliminary results CERES data: Pb+Au at 158 GeV/c Possible topology “Deflection” Raw correlation function Reconstructed signal High-pT at LHC

  23. Alongation: SPS:no(?) RHIC: yes 3-Particle Correlations - DATA at RHIC and SPS CERES STAR preliminary QM’06 QM’06 Au+Au 0-12% High-pT at LHC

  24. 0° Phase Space 180° Another method for 3-particle correlations • Study angular correlations between the associated particles on the away side trigger pt : (2.5-4.0) GeV/c pt : (1.0-2.5) GeV/c S: trigger and accociates from the same event B: trigger, accociate1, associate2 from different events cut on associate Df with respect to trigger trigger Orientation of angles with respect to the trigger Df trig<->ass> 1.0 Count angles: 0-360 deg High-pT at LHC

  25. a.u. PHENIX MC - Chun Zhang QM’06 Project the 2D plot into 1D * plot at * that gives maximum correlation at away side Mach Cone normalized by steeply falling Dfdistribution Deflected Jet flow comp. subtracted Indication of cone structure on the away side ?  needs further investigation * * Monte Carlo studies of the background s/sgeom: (0.0-5.0)% • Monte Carlo construction of non jet-jet • contributions to the measured data • based on the 2 particle conditional yield • and measured elliptic flow. C(Df) data flow*jet + flow*flow No trigger separation cut Preliminary flow*flow Yield of away side pairs C(Df) Preliminary Preliminary Trigger pt : (2.5-4.0) GeV/c Associate pt : (1.0-2.5) GeV/c High-pT at LHC

  26. Yield of away side pairs ? a.u. trigger sep. cutDfTA>1.0 Sructure on the away side also seen with cut around the trigger region T Preliminary Indication of cone structure on the away side ?  needs further investigation High-pT at LHC

  27. Summary • At intermediate pT 2-particle correlations show strong modifications of the away-side structure as compared to p+p collisions – both at RHIC and SPS • Near- and away-side yields are sensitive to the trigger-associated charge combinations – near side: both at RHIC and SPS – away side: only SPS • Preliminary analysis of the 3-particle correlations indicates possible cone-like emission – further analysis in progress – both at RHIC and SPS… ;) • LHC? : Looking forward for the first data… High-pT at LHC

  28. CERES Collaboration D. Adamova, G. Agakichiev, D. Antończyk, A. Andronic, H. Appelshäuser, V. Belaga, J. Bielcikova, P. Braun-Munzinger, O. Busch, A. Castillo, A. Cherlin, S. Damjanovic, T. Dietel, L. Dietrich, A. Drees, S. Esumi, K. Filimonov, K. Fomenko, Z. Fraenkel, C. Garabatos, P. Glässel, G. Hering, J. Holeczek, S. Kniege, V. Kushpil, B. Lenkeit, W. Ludolphs, A. Maas, A. Marin, J. Milosevic, A. Milov, D. Miśkowiec, R. Ortega, Yu. Panebrattsev, O. Petchenova, V. Petracek, A. Pfeiffer, M.Płoskoń, S. Radomski, J. Rak, Ravinovich, P. Rehak, W. Schmitz, J. Schukraft, H. Sako, S. Shimansky, S. Sedykh, J. Stachel, M. Sumbera, H. Tilsner, I. Tserruya, G. Tsiledakis, T. Wienold, B. Windelband, J.P. Wessels, J.P. Wurm, W. Xie, S. Yurevich, V. Yurevich NPI ASCR, Rez, Czech Republic GSI Darmstadt, Germany Frankfurt University, Germany Heidelberg University, Germany JINR Dubna, Russia Weizmann Institute, Rehovot, Israel SUNY at Stony Brook, USA CERN, Switzerland BNL, Upton, USA Münster University, Germany MPI Heidelberg, Germany High-pT at LHC

  29. PYTHIA and UrQMD tests within CERES acceptance Standard PYTHIA sqrt(s) = 17.32 GeV 2-track resolution cut applied Ceres TPC geometrical acceptance 5% central UrQMD – special customized setup(!): Pb+Au @ 160 AGeV, b<5.8fm Pythia called for hard-scatterings with Ecm > 10 GeV, short formation time to allow multiple interactions High-pT at LHC

  30. Pythia (red) and UrQMD (blue) LIKE-SIGN ALL UNLIKE-SIGN High-pT at LHC

  31. 3 Particle correlations : two particle contributions raw correlations yield - (..+..+.. ) = High-pT at LHC

  32. More MC studies (?) Dip at pi in 2-part. correl. – not data-like No dip at pi in 2-part. correl. High-pT at LHC

  33. (Very) preliminary results Pure correlation function !!! No flow subtraction , No normalisation all like sign unlike sign C(Df) Df correlations on top of a steeply falling background (due to orientation of angles with respect to the trigger) a.u. background Df High-pT at LHC

  34. correlations among the associates no trigger separation cut s/sgeom: (0.0-5.0)% Preliminary Preliminary Preliminary like sign all unlike sign Trigger pt : (2.5-4.0) GeV/c Associate pt : (1.0-2.5) GeV/c trigger separation cut DfTA>1.0 s/sgeom: (0.0-5.0)% Preliminary Preliminary Preliminary all like sign unlike sign High-pT at LHC

  35. Energy scan – eta +-1 High-pT at LHC

  36. Energy scan – wide eta High-pT at LHC

  37. Data and Pythia and UrQMD High-pT at LHC

  38. 3-particle correlations – CERES data PRELIMINARY • Limiting factor – statistics: • Example from Au+Au central at RHIC: • Typical S/B = 1/30 • For 3-particle correl: S/B~10-3 • Systematic precision of the order of 10-4 • Estimations for SPS: • number of particles in the associated pT range is 10 on average • most of them are from background(!) • S/B is of about 1/150 • S/B for 3-particle correlations is squared! Only correlation function – no background subtraction High-pT at LHC

  39. High-pT at LHC

  40. High-pT at LHC

  41. High-pT at LHC

  42. High-pT at LHC

  43. High-pT at LHC

  44. _ h Transverse momentum spectra Preliminary Preliminary Mixed event stat. problem Not resolution effect Rapidities 2-2.6 Corrected for efficiency only Present correlations studies :pT 1-4 GeV/c NUCL-EX/0407019 • Measured with TPC • year 2000 data • ~7% centrality No corrections at all 2.1 < h < 2-65 High-pT at LHC

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