1 / 51

Cone is medium response, Ridge is medium itself.

Cone is medium response, Ridge is medium itself. Fuqiang Wang Purdue University For the STAR Collaboration. Bridger ridge, Montana. Plan of talk. Away-side cone: medium response to hard probes. Near-side ridge: medium response or itself ?. High p T trigger particle. Df. trigger jet.

fai
Download Presentation

Cone is medium response, Ridge is medium itself.

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cone is medium response, Ridge is medium itself. Fuqiang Wang Purdue University For the STAR Collaboration

  2. Bridger ridge, Montana Plan of talk • Away-side cone: medium response to hard probes • Near-side ridge: medium response or itself? Flow and Dissipation Workshop, Trento, Sept. 2009

  3. High pTtrigger particle Df trigger jet associatedparticles Away-side p -1 1 0 Df The away-side structure Au+Au PHENIX p+p Flow and Dissipation Workshop, Trento, Sept. 2009

  4. trigger jet away trigger jet trigger jet Mach cone event 1 event 2 Away-side away away deflected jets Df p -1 1 0 Possible physics scenarios pTtrig=3-4 GeV/c, pTassoc=1-2.5 GeV/c Surface bias Flow and Dissipation Workshop, Trento, Sept. 2009

  5. trigger jet away away Mach cone Df2 Df2 trigger jet = f2-ftrig p p event 1 event 2 0 0 0 p 0 p Df1= f1-ftrig away Df1 away deflected jets 3-particle azimuthal correlation signature of conical emission Flow and Dissipation Workshop, Trento, Sept. 2009

  6. Away-side Df2 p 0 0 p Df1 Evidence of conical emission STAR, PRL 102, 052302 (2009) d+Au Au+Au central trigger Flow and Dissipation Workshop, Trento, Sept. 2009

  7. Away-side Conical emission angle STAR, PRL 102, 052302 (2009) trigger q= 1.37 ± 0.02 (stat.) ± 0.06 (syst.) q Constant cone angle vspT suggests Mach Cone shock waves may be the underlying mechanism. Flow and Dissipation Workshop, Trento, Sept. 2009

  8. Higher trigger pT 1 < pTassoc < 2 GeV/c 4 < pTtrig < 6 GeV/c 1 < pTassoc < 2.5 GeV/c 6 < pTtrig < 10 GeV/c 1 < pTassoc < 2.5 GeV/c Flow and Dissipation Workshop, Trento, Sept. 2009

  9.   (z - ut) Theory calculations pQCD + hydro: Neufeld et al. arXiv:0807.2996 quark v = 0.99955 Parton energy loss: Renk et al. PRC 76, 014908 (2007) Flow and Dissipation Workshop, Trento, Sept. 2009

  10. N = 4 Super-Yang-Mills theory in 4d with SU(NC) Chesler & Yaffe arXiv:0712.0050 Heavy quark u = 0.75c AdS/CFT Correspondence Maldacena (1997), Gubser, Klebanov,Polyakov; Witten (1998) A string theory in 5d AdS YM observables at infinite NC and infinite coupling can be computed using classical gravity. Measure heavy quark Mach-cone shock waves:  Experimental consequence of string theory? Flow and Dissipation Workshop, Trento, Sept. 2009

  11. p EOS: p(e) QGP cS= √1/3 = 0.58 HG cS= 0.45 Mixed phase cS= 0 e Speed of sound? qM = 1.37 speed of sound cS~ 0.2 cS far smaller than HG or QGP. Must have mixed phase (phase transition). However, model calculations indicate that Mach Cone angle can be altered by medium flow. Flow and Dissipation Workshop, Trento, Sept. 2009

  12. Investigating flow effect on cone angle

  13. Fit to large Dhazimuthal correlations Au+Au 20-60%, 3<pTtrig<4, 1<pTtrig<2 GeV/c STAR Preliminary 2 Gaus: Ridge at 0 and ridge at p, same shape, diff. magnitudes 2 Gaus: identical conical emission peaks symmetric about p. Flow and Dissipation Workshop, Trento, Sept. 2009

  14. STAR Preliminary • Cone angle takes off after trigger fs=45o. • Split in pT after fs=45o. • Cone angle ~constant over pT at fs<45o. STAR Preliminary Flow and Dissipation Workshop, Trento, Sept. 2009

  15. Is there a back-to-back RIDGE? Away-Side Ridge Away 1 RP Trig. Ridge Near Jet Away 2 Flow and Dissipation Workshop, Trento, Sept. 2009

  16. Away-side Df p -1 1 0 Connection between near- and away-side STAR Preliminary Flow and Dissipation Workshop, Trento, Sept. 2009

  17. Separate 1st and 2nd quadrants trigger particles • Azimuthal correlation for large |Dh|>0.7 • Near-side ridge Gauss repeated at “+π” • Subtract back-to-back symmetric ridge peaks STAR Preliminary ∆φ ∆φ ∆φ ∆φ ∆φ ∆φ ∆φ ∆φ ∆φ ∆φ ∆φ ∆φ Flow and Dissipation Workshop, Trento, Sept. 2009

  18. Away-side asymmetric cone positions STAR Preliminary 1st cone 2nd Cone peak ∆φ RP 2nd Cone trigger 1st cone peak φs • Evidence of flow effect on conical emission. • Important to disentangle flow effect and conical emission angle. Flow and Dissipation Workshop, Trento, Sept. 2009

  19. High-pT trigger particle trigger particle pT > 3 GeV/c d+Au associated particle h ~ 0 h ~ 1 Df ||<0.7 Dh Au+Au ridge assoc. particle pT =1-2 GeV/c Dh Df Bridger ridge, Montana The longitudinal ridge Flow and Dissipation Workshop, Trento, Sept. 2009

  20. What’s already known about ridge • Ridge increases with centrality. • Ridge pt spectrum is a bit harder than bulk. • Ridge particle composition similar to bulk. STAR, arXiv:0909.0191 • Ridge present in untriggered correlation. M. Daugherity (STAR), QM’08, J.Phys.G35:104090,2008

  21. Ridge extended to very large Dh PHOBOS, arXiv:0903.2811 STAR, arXiv:nucl-ex/0701061 2.7<|Dh|<3.9 pTassoc > 1.0 GeV/c STAR Preliminary Flow and Dissipation Workshop, Trento, Sept. 2009

  22. New insights from RP-dependent dihadron correlations

  23. jet ridge Dh cut to “separate” jet and ridge |∆η|>0.7 = ridge + away-side Jet = (|∆η|<0.7) – Accept.*(|∆η|>0.7) assuming ridge is uniform in ∆η. Dh Dh Au+Au 20-60%, 3<pTtrig<4, 1.5<pTtrig<2.0 GeV/c Feng, QM’06. STAR Preliminary d+Au Flow and Dissipation Workshop, Trento, Sept. 2009

  24. Ridge decreases with RP STAR Preliminary Ridge drops when trigger particle moves away from RP. trigger |fs| in-plane out-of-plane Flow and Dissipation Workshop, Trento, Sept. 2009

  25. Chiu,Hwa, arXiv:0809.3018 Correlated Emission Model (CEM) in-plane jet flow aligned more ridge out-of-plane jet flow misaligned less ridge Alignment of jet propagation and medium flow produces the ridge. A model prediction motivated by data Correlated Emission Model (CEM) If correct, would produce measureable asymmetry in near-side ridge correlation peak. Flow and Dissipation Workshop, Trento, Sept. 2009

  26. Konzer, QM’09. STAR Preliminary |∆η|>0.7 Trig. pt=3-4 GeV/c, assoc pt=1-1.5 GeV/c Ridge Jet ∆f = fassoc – ftrig Remove away-side from large Dh correlation Au-Au 20-60% ZYAM -60 to -75 -75 to -90 φs = 0 to -15 -15 to -30 -30 to -45 -45 to -60 0.05 0 • Jet remains constant • Ridge Decreases • Jet symmetric • Ridge asymmetric -1 0 1 π Flow and Dissipation Workshop, Trento, Sept. 2009

  27. Correlation Asymmetry STAR Preliminary trigger pt=3-4 GeV/c v2 syst. Ridge CEM model • Away-side is Asymmetric (not shown in plot). • Jet is symmetric. • Ridge is Asymmetric! • Ridge may be due to • jet-flow alignment. Ridge: assoc pt=1-1.5 GeV/c Ridge: assoc pt=1.5-2 GeV/c Jet: assoc pt=1.5-2 GeV/c Jet in-plane out-of- plane |fs|= ftrig – ψRP Flow and Dissipation Workshop, Trento, Sept. 2009

  28. New insights from 3-particle Dh-Dh correlation

  29. How does long Dh come about? 3-particle - correlations ||<0.7 3<pTtrig<10 GeV/c, 1<pTassoc<3 GeV/c Many models on the market. Netrakanti, QM’09. arXiv:0907.4744STAR Preliminary N. Armesto et al., Phys. Rev. Lett. 93 (2004) 242301 d+Au Central Au+Au Nucleus-Nucleus 2009, August 2009

  30. 3-particle - correlations Netrakanti, QM’09. STAR Preliminary 3<pTtrig<10 GeV/c 1<pTassoc<3 GeV/c ||<0.7 dAu AuAu 12% Charge independent (All) STAR Preliminary AALike = (AALikeTLike + AALikeTUnlike) AAUnlike = All - AALike

  31. jet Separate jet and ridge ridge does not Jet has charge ordering ridge Netrakanti, QM’09. arXiv:0907.4744.STAR Preliminary Same-sign triplets: Only ridge, no jet.

  32. Radial Projection Angular Projection STAR Preliminary  (jet) = 0.25  0.09  (ridge) = 1.53  0.41 Ridge is structureless R x Netrakanti, QM’09. arXiv:0907.4744. STAR Preliminary No prominent subtructures in ridge. Flow and Dissipation Workshop, Trento, Sept. 2009

  33. Ridge-jet cross pairs Netrakanti, QM’09. arXiv:0907.4744. STAR Preliminary Ridge and jet appear to be anti-correlated.

  34. Experimental facts • Ridge increases with centrality. • Ridge spectrum a bit harder than bulk. • Ridge particle composition similar to bulk. • Ridge present in untriggered correlation. • Ridge is mainly in-plane. • Ridge is asymmetric in Df. • Ridge is very wide. • Ridge is random. • No jet-ridge cross-talk. • Ridge may be back-to-back. • Ridge seems unrelated to jet. Now let’s go to models… Flow and Dissipation Workshop, Trento, Sept. 2009

  35. In-medium rad. + long. Flow push N. Armesto et al., Phys. Rev. Lett. 93 (2004) 242301 • Ridge increases with centrality. • Ridge spectrum a bit harder than bulk. • Ridge particle composition similar to bulk. • Ridge present in untriggered correlation. • Ridge is mainly in-plane. • Ridge is asymmetric in Df. • Ridge is very wide. • Ridge is random. • No jet-ridge cross-talk. • Ridge may be back-to-back. • Ridge seems unrelated to jet. x x x x

  36. Turbulent color field A. Majumder et al., Phys. Rev. Lett. 99 (2004) 042301 • Ridge increases with centrality. • Ridge spectrum a bit harder than bulk. • Ridge particle composition similar to bulk. • Ridge present in untriggered correlation. • Ridge is mainly in-plane. • Ridge is asymmetric in Df. • Ridge is very wide. • Ridge is random. • No jet-ridge cross-talk. • Ridge may be back-to-back. • Ridge seems unrelated to jet. x x

  37. Recombination of thermal+showerpartons R.C. Hwa, C.B. Chiu, Phys. Rev. C 72 (2005) 034903 • Ridge increases with centrality. • Ridge spectrum a bit harder than bulk. • Ridge particle composition similar to bulk. • Ridge present in untriggered correlation. • Ridge is mainly in-plane. • Ridge is asymmetric in Df. • Ridge is very wide. • Ridge is random. • No jet-ridge cross-talk. • Ridge may be back-to-back. • Ridge seems unrelated to jet. x x x

  38. Momentum kick model C.Y. Wong hep-ph:0712.3282 • Ridge increases with centrality. • Ridge spectrum a bit harder than bulk. • Ridge particle composition similar to bulk. • Ridge present in untriggered correlation. • Ridge is mainly in-plane. • Ridge is asymmetric in Df. • Ridge is very wide. • Ridge is random. • No jet-ridge cross-talk. • Ridge may be back-to-back. • Ridge seems unrelated to jet. x x x x

  39. Transverse flow boost S.A. Voloshin, Phys. Lett. B 632 (2006) 490; E. Shuryak, Phys. Rev. C 76 (2007) 047901 • Ridge increases with centrality. • Ridge spectrum a bit harder than bulk. • Ridge particle composition similar to bulk. • Ridge present in untriggered correlation. • Ridge is mainly in-plane. • Ridge is asymmetric in Df. • Ridge is very wide. • Ridge is random. • No jet-ridge cross-talk. • Ridge may be back-to-back. • Ridge seems unrelated to jet. x

  40. Glasma flux tube fluctuation + radial flow R. Venugopalan et al., arXiv:0902.4435 • Ridge increases with centrality. • Ridge spectrum a bit harder than bulk. • Ridge particle composition similar to bulk. • Ridge present in untriggered correlation. • Ridge is mainly in-plane. • Ridge is asymmetric in Df. • Ridge is very wide. • Ridge is random. • No jet-ridge cross-talk. • Ridge may be back-to-back. • Ridge seems unrelated to jet. ridge ridge x Fluctuation of color flux tubes  excess ridge particles (larger in-plane due to flow?)

  41. Summary and open questions • Conical emission of correlated particles.Medium response to hard probes. Suggests Mach cone shock waves. • What distortion to Mach angle by medium? • How to extract speed of sound? EOS? • Ridge is uniform in pseudo-rapidity.Likely medium itself at early time. • Is it due to color flux tubes? • What additional work to falsify this and othermodels, or learn something from them? Flow and Dissipation Workshop, Trento, Sept. 2009

  42. Backups

  43. v2 systematic uncertainties Flow and Dissipation Workshop, Trento, Sept. 2009

  44. RP-frame cumulant Jet-like 3-p correlation Lab-frame cumulant On-diag projection On-diag projection Off-diag projection Off-diag projection Flow and Dissipation Workshop, Trento, Sept. 2009

  45. Flow and Dissipation Workshop, Trento, Sept. 2009

  46. trigger particle pT > 3 GeV/c Df assoc. particle pT =1-2 GeV/c Large combinatorics pTtrig=3-4 GeV/c, pTassoc=1-2 GeV/c N jet particles ~ 1, N bkgd particles ~ 20 Combinatorial pair bkgd is huge! Extremely difficult analysis. Careful subtraction of bkgd. Extensive assessment of systematics. Flow and Dissipation Workshop, Trento, Sept. 2009

  47. What’s left on the away-side? 0.2 4 second peak 0.6 3 0.5 Peak position Peak area 0.1 first peak 0.4 2 Peak s 0 p/2 φs φs φs Differential pathlength sensitivity Peak distance Flow and Dissipation Workshop, Trento, Sept. 2009

  48. STAR Preliminary • Jet s constant with fs. • Ridge s decreases with fs. • Cone s increases with fs. STAR Preliminary • Jet s decreases with pT. • Ridge s constant with pT. • Cone s decreases with pT. Flow and Dissipation Workshop, Trento, Sept. 2009

  49. STAR Preliminary ||<0.7 ||<0.7 Ridge 2-particle correlation AuAu ZDC central (0-12%) triggered data, 3<pTTrig<10 GeV/c, 1<pTAsso<3 GeV/c Black : Raw signal Pink:Mixed-event background Blue : Scaled bkgd by ZYA1 Red : Raw signal – bkgd Dh acceptance corrected Flow and Dissipation Workshop, Trento, Sept. 2009

  50. - - 3-particle correlation background • Raw  Raw Raw signal • Raw  Bkg Hard-Soft • Bkg1  Bkg1 • Bkg1  Bkg2 correlated Soft-Soft Flow and Dissipation Workshop, Trento, Sept. 2009

More Related