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In-Medium Properties of Jets

In-Medium Properties of Jets. In-Medium. Medium Properties. Jets. from. Fuqiang Wang. Outline. “punch-through” at high p T “disappearance” at intermediate p T enhancement at low p T medium collective response. mid-rapidity (the most interesting region):

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In-Medium Properties of Jets

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  1. In-Medium Properties of Jets In-Medium Medium Properties Jets from Fuqiang Wang

  2. Outline • “punch-through” at high pT • “disappearance” at intermediate pT • enhancement at low pT • medium collective response mid-rapidity (the most interesting region): will not cover forward-rapidity jet-correlation. away-side (strongest modification): will not cover near-side correlation, Dh long range correlation. charged hadrons (large statistics): will not cover identified hadron, or g-h, or e-h correlations. Quark Matter 2006, Shanghai, China – Fuqiang Wang

  3. clear away-side peak – dijets little modification on near side suppression of away-side yield but little modification to away-side shape punch-through at high pT STAR, PRL 97 (2006) 162301. 8 < pT(trig) < 15 GeV/c J. Jia (PHENIX), nucl-ex/0510019. Quark Matter 2006, Shanghai, China – Fuqiang Wang

  4. 6<pT(trig)<8 GeV/c 1 Au+Au 40-80% 2 Magestro (STAR), QM 2005. 1 3 2 3 no change in away-side shape 8 < pT(trig) < 15 GeV/c away-side widths similar for central and peripheral, also for different pT. • finite prob. of not interacting: fragmentation as in vacuum? • fragment in medium, then hadrons lose energy with insignificant broadening at large pT? • lose some energy, and then fragment? Quark Matter 2006, Shanghai, China – Fuqiang Wang

  5. “disappearance” at intermediate pT • near-side unchanged • away-side nearly disappeared -consistent with “surface emission” • d+Au ~ p+p: final state effect • qualitatively intuitive for jet-suppression, but quantitatively not simple. Cu+Cu less suppressed, consistent with pathlength difference. away-side yield seen above background Cu+Cu top 10% Quark Matter 2006, Shanghai, China – Fuqiang Wang

  6. J. Jia (PHENIX), nucl-ex/0510019. STAR, PRL93 (2004) 252301. |ftrig-fRP| reaction plane dependence Hint of stronger suppression out-of-plane than in-plane, consistent with energy loss picture. Hint of stronger double-peak structure out-of-plane than in-plane. Quark Matter 2006, Shanghai, China – Fuqiang Wang

  7. hard <pT> from away jets Away side <pT> (GeV/c) soft similar <pT> from medium decay enhanced, broadened, softened at low pT STAR, PRL95 (2005) 152301. F.Wang (STAR), QM’05, nucl-ex/0510068. pTtrig=4-6 GeV/c pTassoc=0.15-4 GeV/c • Enhanced correlated yields. • Broadened and softened away-side. hard-soft: approach thermalization. soft-soft (larger x-section): higher degree of thermalization. Quark Matter 2006, Shanghai, China – Fuqiang Wang

  8. J.G. Ulery (STAR), QM’05, nucl-ex/0510055;M. Horner, parallel 3.2, Nov.19. PHENIX, PRL97 (2006) 052301. dashed=PHENIX, solid=STAR*0.35 away 0-5% 5-10% hump STAR Preliminary 20-40% 10-20% 40-60% 60-80% PHENIX, nucl-ex/0611019. double-humped for some pT ranges trigger pT =2.5-4 GeV/c, associated pT =1.0-2.5 GeV/c • Away-side center does not drop (stays roughly constant). • The hump increases with centrality: shock wave excitation? Quark Matter 2006, Shanghai, China – Fuqiang Wang

  9. J. Jia (PHENIX), nucl-ex/0510019. 2.5<pT(trig)<4 GeV/c <pT> is dipped at p ! F.Wang (STAR), QM’05, nucl-ex/0510068. Away side <pT> (GeV/c) Hadrons in the double-hump are harder:shock wave push? Quark Matter 2006, Shanghai, China – Fuqiang Wang

  10. near-side trigger near Medium away-side jet axis away projection Rudy Hwa Df Df deflected jets high pT parton shock wave push? Scheid, Muller, Greiner, Phys. Rev. Lett. 32, 741 (1974); Hofmann, Stoecker, Heinz, Scheid, Greiner, PRL 36, 88 (1976). Many recent studies: Stoecker, nucl-th/0406018; Casalderrey-Solana, Shuryak, Teaney, hep-ph/0411315; Ruppert, Muller, hep-ph/0503158; Chaudhuri, Heinz, nucl-th/0503028; Renk, Ruppert, PRC73 (06) 011901, Y.G. Ma, et al., nucl-th/0601012. … Perfect fluid of hot and dense matter at RHIC: cS, supersonic jets, jet-quenching. RHIC appears to have all the conditions to generate Mach-cone shock waves. Double-peak structure can also be generated by large angle gluon radiation: Vitev, Phys. Lett. B630 (2005) 78; A.D. Polosa and C.A. Salgado, hep-ph/0607295; …or deflected jets. deflected jets: well confined in each event but deflected at varying angle. preferential selection of jet particles: those directed inwards are harder to get out because of energy loss. Quark Matter 2006, Shanghai, China – Fuqiang Wang

  11. near near near Δ2 Δ2 π π Medium Trigger Medium Medium away away Δ2 0 0 Δ1 π away π Δ1 Δ1 0 0 di-jets Δ2 π 0 deflected jets π Δ1 0 mach cone discrimination by 3-particle correlation Need 3-particle correlation to discriminate different physics mechanisms. Quark Matter 2006, Shanghai, China – Fuqiang Wang

  12. jet bkgd Trigger Δ2 Δ1 3-particle correlation backgrounds Jason Ulery (STAR), HP’06, nucl-ex/0609047; J.G. Ulery, FW, nucl-ex/0609017. Claude Pruneau, STAR talk, Parallel 1.3, Nov.15; Jason Ulery, STAR poster # 44. raw = (jet+bkgd) x (jet+bkgd) jet x jet = raw – (bkgd x bkgd) – (jetx bkgd) 1/Ntrig d2N/dDf1dDf2 Δ2 pTtrig=3-4 GeV/c pTassoc=1-2 GeV/c Δ1 jetx bkgd bkgd x bkgd - + trigger flow trigger flow Quark Matter 2006, Shanghai, China – Fuqiang Wang

  13. pp d+Au Au+Au 50-80% Au+Au 30-50% Au+Au central 0-12% ZDC Δ2 Au+Au 10-30% Au+Au 0-10% Δ1 3-particle correlation signal J.G. Ulery (STAR), HP’06, nucl-ex/0609047; Claude Pruneau, STAR talk, Parallel 1.3; Jason Ulery, STAR poster # 44. pTtrig=3-4 GeV/c, pTassoc=1-2 GeV/c 1/Ntrig d2N/dDf1dDf2 • Elongation along away diagonal: kT broadening, deflected jets. • Evidence of conical emission in central Au+Au collisions. Quark Matter 2006, Shanghai, China – Fuqiang Wang

  14. Major sources of systematic errors: flow, background normalization. Conical emission signal in central Au+Au. Other contributions (such as deflected jets) present. projection along off-diagonaldiagonal 1/Ntrig d2N/dDf1dDf2 1/Ntrig dNtriplet/dDf Au+Au central 0-12% ZDC =(1+2)/2 =(1-2)/2 Δ2 1/Ntrig dNtriplet/dDf Δ1 =(1-2)/2 =(1+2)/2-p ZDC central 12% Au+Au Quark Matter 2006, Shanghai, China – Fuqiang Wang

  15. Au+Au 0-12% ZDC cone angle (radians) Δ2 (Npart/2)1/3 Δ1 Au+Au ZDC 12% Au+Au 0-50% cone angle (radians) pTassoc (GeV/c) cone angle Jason Ulery, STAR poster # 44. 1/Ntrig d2N/dDf1dDf2 Cone angle consistent with no pT dependenc  Conical emission consistent with Mach-cone shock waves, notsimple Cerenkov gluon radiation. Cone angle: q ~ 1.45 ~ 80o cos(q) ~ 0.12 =??? cS Quark Matter 2006, Shanghai, China – Fuqiang Wang

  16. Au+Au 0-12% ZDC Δ2 Δ1 3-particle signal strength J.G. Ulery (STAR), HP’06, nucl-ex/0609047; STAR poster # 44. 1/Ntrig d2N/dDf1dDf2 Away Cone Deflected + Cone signal / radian2 (Npart/2)1/3 Quark Matter 2006, Shanghai, China – Fuqiang Wang

  17. Same Side Away Side polar coord. analysis N.N. Ajitanand (PHENIX), poster # 39. • Background from mixed-events. • Background subtracted. • 3-particle correlation in PHENIX acceptance, consistent with MC. Quark Matter 2006, Shanghai, China – Fuqiang Wang

  18. Conclusions • Di-jets present in heavy ions at sufficiently high pT. Angular distribution little modified, correlated yield per trigger strongly suppressed. • At intermediate pT, di-jets strongly suppressed that no appreciable di-jets survive. • Rich phenomena at low pT: enhanced, broadened (even double-humped), and softened. The <pT> is the lowest at p. • Three-particle jet-correlation: Evidence for conical emission. Cone angle ~ 1.45. Quark Matter 2006, Shanghai, China – Fuqiang Wang

  19. backups Quark Matter 2006, Shanghai, China – Fuqiang Wang

  20. Enhancement at low pt STAR, PRL95 (2005) 152301. Enhanced and broadened away-side distribution at low pT. Quark Matter 2006, Shanghai, China – Fuqiang Wang

  21. Au+Au 0-12% ZDC Δ2 ZDC Δ1 3-particle signal strength J.G. Ulery (STAR), Hard Probes 06, nucl-ex/0609047; QM’06 poster # 44. • Major sources of systematic errors: flow, background normalization. • Mach cone signal in central Au+Au collisions. • Contribution from deflected jets present. 1/Ntrig d2N/dDf1dDf2 Quark Matter 2006, Shanghai, China – Fuqiang Wang

  22. _ _ Flow systematics reaction plane v2 • Flow is varied between the modified reaction plane result and the 4- particle cumulant result. • Result is robust with the variation in v2. 4-particle cumulant v2 Jason Ulery (STAR), Hard Probes 2006. Quark Matter 2006, Shanghai, China – Fuqiang Wang

  23. Background normalization systematic default • Normalization within |Δ±1|<0.175 assuming zero yield at minimum. • Default uses a normalization range of 0.35. • Normalization range of 0.70 used to check systematic. • Result is robust with respect to normalization range. Jason Ulery (STAR), Hard Probes 2006. wide norm. region Quark Matter 2006, Shanghai, China – Fuqiang Wang

  24. v2(jet) = v2(trig) v2(jet) = 0 Δ2 Filled: v2(jet) = v2(trig) Open: v2(jet) = 0 Au+Au 0-12% Δ1 (1+2)/2 (1+2)/2 (1+2)/2 (1-2)/2 (1-2)/2 (1-2)/2 Quark Matter 2006, Shanghai, China – Fuqiang Wang

  25. cumulant vs jet-like with no flow J.G. Ulery, FW, nucl-ex/0609017. Quark Matter 2006, Shanghai, China – Fuqiang Wang

  26. cumulant vs jet-like with flow J.G. Ulery, FW, nucl-ex/0609017. Quark Matter 2006, Shanghai, China – Fuqiang Wang

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