1. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 1 KANETA, Masashi for the PHENIX Collaboration RIKEN-BNL Research Center  0 v 2 study in  s NN = 200GeV Au+Au collisions

2. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 2 Why Event Anisotropy? Because of sensitive to collision geometry –In low p T (~<2 GeV/c) Pressure gradient of early stage Hydrodynamical picture is established –In high p T (>~2 GeV/c) Energy loss in dense medium (Jet Quenching) Partonic flow(?) x z y Here we focus on ellipticity of azimuthal momentum distribution, v 2 (second Fourier coefficient)

3. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 3 PHENIX Experiment Lead Scintillator and Lead Glass EMCs –Gamma measurement ( 0 ) BBCs and ZDCs –Collision centrality determination BBCs –Reaction plane determination and –Its resolution correction

4. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 4 BBC in PHENIX NorthSouth 144.35 cm ⊿ η = 3.1 ~ 4.0 ⊿ φ = 2π 64 elements Quartz Cherenkov radiator meshed dynode PMT inner ring middle ring outer ring BBC

5. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 5 PbGl and PbSc EMC’s 1 Sector = 6x3 Supermodules (SM) 1 PbSc SM = 12x12 towers PbSc towers: 5.52 x 5.52 x 33 cm 3 (18 X 0 ) 15552 blocks total 1 PbSc tower: 66 sampling cells 1.5 mm Pb, 4 mm Sc Ganged together by penetrating wavelength shifting fibers for light collection Readout: FEU115M phototubes 2 Sectors PbGl 1 PbGl Sector 16x12 supermodules (SM) 1 PbGl SM 6x4 towers Separate reference system 1 FEM Reads out 2x3 supermodules or 12x12 towers

6. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 6 Method of  0 v 2 Measurement Define reaction plane by charged multiplicity on Beam-Beam Counters  0 reconstruction from gamma measured by Electro-Magnetic Calorimeter (EMC) For each p T, azimuthal angle, centrality Combine both information –Counting number of  0 as a function of event anisotropy parameter measured azimuthal angle of the particle reaction plane angle v n real = v n measured / ( reaction plane resolution ) n Note: the detail of reaction plane definition will be found in nucl-ex/0305013

7. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 7 Reaction Plane Defined by BBC’s BBC north and south (~3-4) are used Resolution calculation –Two sub-events are selected –North and south -  /2  /2 Correlation of two BBC’s

8. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 8  0 Identification Requirement for photon –Dead and noisy EMC towers are removed for the analysis –Energy of shower on EMC>0.040 [GeV] –PID cuts:  2 <3 for photon probability –|TOF|<1.2 [ns] –Note: those cut are loser than single p T distribution analysis For  0 –Asymmetry cut: |E 1 –E 2 | / ( E 1 +E 2 ) < 0.8 –Combinatorial background is estimated by event mixing Classes categorized for event mixing –centrality : every 10% –BBC Z Vertex : every 10cm in ±30cm –reaction plane direction in PHENIX detector : 24 bins in ±

9. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 9 Example Plots from the Analysis Procedure Invariant mass of  from same event and mixed event (classed by reaction plane, centrality, vertex position) normalization range for combinatorial B.G. subtraction After subtraction, there is 2nd component of B.G. in p T <2GeV/c region shape assumed as linear+asym. Gauss count number of  0 in a range after 2nd B.G. subtraction (not used the fit function) m  [GeV/c 2 ] 200GeV Au+Au m  [GeV/c 2 ]  R [rad] Fit function: (average of  0 count)  ( 1 + 2 v 2 cos[2(  -  R )]) Green lines : deviation by error of v 2

10. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 10 One of difficulties (?) is.. The analysis of   v 2 –Counting number of  0 as a function of centrality, p T and - R –The analyses (fitting of combinatorial background, its subtraction, counting  0 and so on) are done by macro automatically –However, we need to think it is not perfect, that is, it may fail sometime Therefore,....

11. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 11 Toooooooooo many histograms checked by eyes After combinatorial background subtraction Example of invariant mass distributions for each p T,  -  R in a centrality bin Before combinatorial background subtraction  0 as a function of  Rb

12. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 12 v 2 vs. p T vs. Centrality from 200GeV Au+Au Statistical error is shown by error bar Systematic error from  0 count method and reaction plane determination is shown by gray box phenix preliminary

13. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 13 } nucl-ex/0305013 phenix preliminary v 2 vs. p T vs. Centrality from 200GeV Au+Au Statistical error is shown by error bar Systematic error from  0 count method and reaction plane determination is shown by gray box Charged + K v 2 consistent with  0 v 2 in p T <4GeV/c The charged  and K v 2 are shown only with statistical errors

14. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 14 phenix preliminary v 2 vs. p T (Minimum Bias) from 200GeV Au+Au Identified particle v 2 up to p T =10GeV/c 36.3  10 6 [events] = 5.3 +0.5-0.4 [(  b) -1 ]

15. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 15 } nucl-ex/0305013 phenix preliminary v 2 vs. p T (Minimum Bias) from 200GeV Au+Au Identified particle v 2 up to p T =10GeV/c 36.3  10 6 [events] = 5.3 +0.5-0.4 [(  b) -1 ]

16. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 16 phenix preliminary nucl-ex/0305013 v 2 vs. p T (Minimum Bias) from 200GeV Au+Au Identified particle v 2 up to p T =10GeV/c 36.3  10 6 [events] = 5.3 +0.5-0.4 [(  b) -1 ]

17. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 17 Comparison with K 0 S and  (STAR) STAR data from nucl-ex/0306008

18. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 18 Quark Coalescence? Phys. Rev. Lett. 91 (2003) 092301, D.Molnar and S.A. Voloshin qqmeson, qqq(qqq)Baryon How data looks like? - - - - Non-strange and strange meson and baryon seems to be merged around p T /n quark 1-3GeV/c But we need more statistics to conclude it

19. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 19 Comparison with a model phenix preliminary Hydrodynamical calculation agreed in p T ~<2 GeV/c. After that, it is deviated. Hydrodynamical calculation

20. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 20 Comparison with a model which is described in nucl-th/0306027. Here we don't want to discuss which model can describe the data. To conclude which model can describe the data, we need much more statistics in high p T region. Special thanks to C. Nonaka (one of authors) of nucl-th/0306027 for data of model calculation Comparison with a model phenix preliminary

21. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 21Summary First measurement of  0 v 2 at RHIC –In p T =1-10 GeV/c –v 2 of the highest p T from identified particle Charged  v 2 consistent with  0 v 2 –In p T =1-3GeV/c Minimum bias data shows finite  0 v 2 –Up to p T ~8 GeV/c Special thanks to LBL and STAR people, especially Art Poskanzer –I learned all of event anisotropy analysis when I was here

22. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 22Outlook Feature plan of analysis –Using high p T gamma trigger in run2 Au+Au data We will have about twice statistics in high p T need to study trigger bias –therefore, present analysis results are from minimum bias trigger events – v 2 is also available by same method –PHENIX has photon v 2 also (STAR also, but not opened yet) –photon v 2, especially low p T ! RHIC run4 Au+Au, it will be –Much more statistics Detail study of v 2 shape around p T =2-4GeV/c –Much higher p T We want to know where is the end of finite v 2 in very high p T

23. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 23 Future Plan of Event Anisotropy Analysis in PHENIX Trying v 2 for all of possible particles with large statistics –Already tried charged ,K,p, deuteron,  0, e +(-) (inclusive), gamma (inclusive) –On going but need much more statistics eta direct gamma –inclusive gamma – [contribution from  0, eta (dominantly)] charm and bottom meson –inclusive e +(-) – [contribution from  0 and eta dalitz decay (dominantly)] –Seems to be hard work, but... K 0 s Lambda resonances penta-quark v 1 on BBC (=3-4) Correlation method for v n Cross section and HBT radii in-plane and out-plane

24. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 24 Electron and Positron v 2 p T [GeV/c] v2v2 From talk of Singo Sakai (Ph.D student at Tsukuba Univ.) at JPS autumn meeting 2003 and DNP2003 PHENIX preliminary 200 GeV Au+Au Min. Bias

25. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5) 25 Photon v 2 PHENIX preliminary 200 GeV Au+Au Min. Bias STAR from my analysis (not finished...) v2v2 p T [GeV/c] From DNP2003 talk Saskia Mioduszewski, Edouard Kistenev, and ShinIchi Esumi