Global and Collective Dynamics at PHENIX

Transcription

1 Global and Collective Dynamics at PHENIX Takafumi Niida for the PHENIX Collaboration University of Tsukuba Heavy Ion collisions in the LHC era in Quy Nhon

2 outline n Introduction of v n n Higher harmonic flow (v n ) of Identified particle n particle correlations with v n n Azimuthal HBT w.r.t event plane n Summary

3 Higher harmonic event plane n Initial density fluctuations cause higher harmonic flow v n n Azimuthal distribution of emitted particles: Ψ 3 Ψ dn dφ 1+ v cos( φ Ψ ) +v 3 cos( φ Ψ 3 ) +v 4 cos( φ Ψ 4 ) v = cosn( φ Ψ ) n n Ψ 4 Ψ n : Higher harmonic event plane φ : Azimuthal angle of emitted particles 3

4 v n measurement via Event plane method RXN in: 1.5< η <.8 & out: 1.< η <1.5 MPC: 3.1< η <3.7 BBC: 3.< η <3.9 ZDC/SMD -5 CNT: η <.35 dn/dη 5 v = cosn( φ Ψ ) n n η Ψ n : Determined by forward detector RXN φ : Measured at mid-rapidity 4

5 Charged hadron v n at PHENIX PRL n v increases with increasing centrality, but v3 doesn t n v 3 is comparable to v in -1% n v 4 has similar dependence to v 5

6 v 3 breaks degeneracy f g.3 (a) p = GeV/c T (b) p T PRL = GeV/c v v 3. PHENIX KLN + 4 πη/s = Glauber + 4πη/s = 1 (1) n v 3 provides new constraint on hydro-model parameters ² Glauber & 4πη/s=1 : works better ² KLN & 4πη/s= : fails (c) p = GeV/c T UrQMD + 4πη/s = Glauber + 4πη/s = 1 () 1 3 N part V V (d) p = GeV/c T 1 3 N part

7 Recent Results at PHENIX n v n of Identified particle n particle correlations with v n n Azimuthal HBT w.r.t event plane 7

8 Motivation of PID v n n v n is sensitive probe to the QGP bulk property n Important to check the following features seen in v ² Mass splitting at low p T ² Baryon/Meson difference at mid p T ² How is the scaling property of v n? 8

9 v n of Identified particle V n. 5 GeV Au+Au -5% v {Φ }. π + π - - K K pp :p T + 5 correlated sys. of π ± PHENIX Preliminary v 3 {Φ 3 }x p [GeV/c] n Mass splitting at low p T : Hydrodynamics. T v 4 {Φ 4 }x v 4 {Φ }x5. n Baryon/Meson difference at mid p T : Quark coalescence 9

10 PID v n with modified scaling n/ V n /n q GeV Au+Au -5% / v {Φ }/n q π + π K K pp :KE correlated sys. of π ± T PHENIX Preliminary 3/ v 3 {Φ 3 }/n q x.5 n Known n q scaling fails in v 3, v 4 n Modified scaling works well for v n : v n (KE T /n q )/n q n/ 1 4/ v 4 {Φ 4 }/n q x / v 4 {Φ }/n q x KE T /n q [GeV]

11 PID v at high p T PRC (1) n Extend PID to high p T by combining TOF(MRPC) and Aerogel Cherenkov Counter n Quark number scaling is better for KE T /n q than p T /n q n But it breaks at KE T /n q ~.7GeV for non-central collisions v /n q v /n q v % (a) K +K p+p -% -6% v X 1.6 for -% p (GeV/c) T (c) (GeV) KE T /n q (e) -6% (b) p (GeV/c) T (d) (GeV) KE T /n q (f) (GeV/c) p T /n q Au+Au s NN = GeV (GeV/c) p T /n q. 11

12 Recent Results at PHENIX n v n of Identified particle n particle correlations with v n n Azimuthal HBT w.r.t event plane 1

13 Motivation of particle correlations with v n < p T asso < p T trig GeV/C Phys. Rev. C 8, 6491 (9) Phys. Rev. C 78, 1491 (8) Ridge v subtracted Δφ Jet( φ) =CF( φ) b Flow( φ) n Ridge and Shoulder can be seen in Δφ-Δη correlation ² They can be explained by v n? n v n subtractions are needed to get real jet correlations Shoulder :p+p : Au+Au 13

14 particle correlations with Δη gap Pb+Pb.76TeV QM 11 J. Jia ATLAS Flow Plenary n v n reproduce Ridge & Shoulder well in -5% 14

15 particle correlations without Δη gap PHENIX PRELIMINARY Au+Au GeV -% inc. γ-had. V, V 3 & V 4 (Φ 4 ) ZYAM subtracted n Most-central : Away side yield are suppressed n Mid-central : Away side yield still remain 15

16 Recent Results at PHENIX n Particle Identified v n n particle correlations with vn n Azimuthal HBT w.r.t event plane 16

17 Motivation of Azimuthal HBT w.r.t v plane Initial spatial anisotropy (eccentricity) momentum anisotropy v How is final eccentricity? v Plane n Final eccentricity can be measured by azimuthal HBT Δφ ² It depends on Initial eccentricity, pressure gradient, expansion time, and velocity profile etc ² Good probe to investigate system evolution 17

18 Azimuthal HBT radii for kaons n Observed oscillation for R side, R out, R os n Final eccentricity is defined as ε final = R s, / R s, ² R s,n = R s,n (Δφ)cos(nΔφ) PRC7, 4497 (4) in-plane 18

19 Eccentricity at freeze-out R s,n = R s,n (Δφ)cos(nΔφ) ε final = R s, R s, PRC7, 4497 (4) n ε final ε initial / for pion ² Indicates that source expands to in-plane direction, and still elliptical ² PHENIX and STAR results are consistent n ε final ε initial for kaon ² Freeze-out time is faster than that of pion? ² Due to different m T between 19

20 k T dependence of azimuthal pion HBT radii ] [fm ] [fm ] [fm R s 15 R o 15 R l λ Δφ [rad] Δφ [rad] ] [fm R os n Oscillation can be seen in R s, R o, and R os for each kt regions Δφ [rad] Δφ [rad] Δφ [rad] PHENIX Preliminary - - Au+Au GeV π + π + & π π centrality: -6% kt.-.3 kt.3-.4 kt.4-.5 kt.5-.6 kt.6-.8 kt.8-1.5

21 m T dependence of ε final m T = k T + m ε final.4.3. PHENIX Preliminary Au+Au GeV π π +π π -% π π +π π -6% K + K + +K + + K K +K - K K -% -6% <m T > [GeV/c] n ε final of pions increases with m T in most/mid-central collisions n There is still difference between π/k even in same m T ² But the difference is at most within σ of systematic errors 1

22 m T dependence of relative amplitude.4 Rs, / Rs,.3 -Ro, / Ro,.4 -Rl, / Rl, Ro, / Rs,.3. R os, / Rs, <m T > [GeV/c] <m T > [GeV/c] <m T > [GeV/c] PHENIX Preliminary Au+Au GeV - - π + π + +π π - - π + π + +π π K K +K K K K +K K -% -6% -% -6% n Relative amplitude of R out in -% doesn t depend on m T ² Does it indicate emission duration between in-plane and out-ofplane is different?

23 Azimuthal HBT w.r.t v 3 plane Initial spatial fluctuation (triangularity) momentum anisotropy triangular flow v 3 n Final triangularity could be observed by azimuthal HBT w.r.t v 3 plane(ψ 3 ) if it exists at freeze-out ² Detailed information on space-time evolution can be obtained n Analysis is ongoing Ψ 3 Ψ 3 3

24 Summary n v n of Identified particle ² PID v n have been measured ² Modified scaling v n (KE T /n q )/n q n/ works well for v n ² Quak number scaling for v breaks at high p T in non-central collisions n particle correlations with v n ² Away side yield are suppressed in most central collisions, but still remain in non-central collisions n Azimuthal HBT w.r.t v plane ² ε final increase with m T, while relative R out, doesn t depend on m T in central collisions ² Difference of ε final between π/k is seen even in same m T, but note it is within σ of sys. error 4

25 Back up 5

26 PID v n vs centralarity V n Au+Au s NN = GeV PHENIX Preliminary.3 v {Φ } -1%.3 1-%.3-3%.3 3-5%.5 π + π -.5 :p correlated sys..5 of π.5.. ± + -. T K K. 5 pp v3 {Φ 3 } x, -1%.3 1-%.3-3%.3 3-5% v4 {Φ 4 } x1.8, -1%.3 1-%.3-3%.3 3-5% v4 {Φ } x5., -1%.3 1-%.3-3%.3 3-5% p T [GeV/c] Same trends are seen in each centrality bins 6

27 v at high p T vs centrality v /n q v /n q % K +K p+p -4% - (a) (c) 1-% 4-6% Au+Au s NN (b) (d) = GeV KE T /n q (GeV) KE T /n q (GeV) Scaling starts breaking at 1-% 7

28 m T dependence of azimuthal pion HBT radii in -% ] [fm R s λ Δφ [rad] ] [fm R o ] [fm R os Δφ [rad] ] [fm R l Δφ [rad] PHENIX Preliminary - - Au+Au GeV π + π + & π π centrality: -% kt.-.3 kt Δφ [rad] Δφ [rad] kt.3-.4 kt.4-.5 kt.6-.8 kt

29 What is HBT? n Quantum interference between identical two particles n Powerful tool to explore space-time evolution in HI collisions n HBT can measure the source size and shape at freeze-out, Not whole size But homogeneity region in expanding source C P( p1, p) = P( p1) P( p) 1 ~ = + ρ( q ) = 1+ exp( R q inv inv) P(p 1 ) : Probability of detecting a particle P(p 1,p ) : Probability of detecting pair particles assuming gaussian source q = p 1 p p1 + p kt = q k, q p 1 side T out detector // k T 1/R p detector 9

30 3D HBT radii n Out-Side-Long system ² Bertsch-Pratt parameterization n Core-halo model ² Particles in core are affected by coulomb interaction C = C core + C halo = [λ(1+ G)F]+[1 λ] G = exp( R inv q inv ) = exp( R side q side R out q out R long q long R os q side q out ) R long : Longtudinal size R side : Transverse size R out : Transverse size + emission duration R os : Cross term between Out and Side p 1 p Sliced view R out R side detector detector 3

31 The past HBT Results for charged pions and kaons n Centrality / m T dependence have been measured for pions and kaons ² No significant difference between both species centrality dependence m T dependence 31

32 Analysis method for HBT n Correlation function C = R(q) M(q) ² Ratio of real and mixed q-distribution of pairs q: relative momentum n Correction of event plane resolution ² U.Heinz et al, PRC66, 4493 () n Coulomb correction and Fitting ² By Sinyukov s fit function ² Including the effect of long lived resonance decay core halo C = C + C G = [ λ(1 + G) F] + [1 λ] = exp( R side q side R out q out R long q long R os q side q out ) 3

33 1D Inv 3D Side Out Long Correlation function for charged pions n Raw C for 3-6% centrality n Solid lines is fit functions R.P R.P R.P R.P 33

34 Azimuthal HBT radii for pions n Observed oscillation for R side, R out, R os n Rout in -1% has oscillation ² Different emission duration between in-plane and out-of-plane? out-of-plane in-plane 34

35 Correlation function for charged kaons n Raw C for -6% 1D Inv 3D Side Out Long R.P R.P R.P R.P 35

36 STAR Result (w.r.t psi) n PRL.93, 131(4) 36