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p 0 v 2 study in  s NN = 200GeV Au+Au collisions

p 0 v 2 study in  s NN = 200GeV Au+Au collisions. KANETA, Masashi for the PHENIX Collaboration RIKEN-BNL Research Center. Why Event Anisotropy?. y. z. x. Because of sensitive to collision geometry In low p T (~<2 GeV/c) Pressure gradient of early stage

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p 0 v 2 study in  s NN = 200GeV Au+Au collisions

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  1. p0 v2 studyin sNN = 200GeV Au+Au collisions KANETA, Masashi for the PHENIX Collaboration RIKEN-BNL Research Center Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

  2. Why Event Anisotropy? y z x • Because of sensitive to collision geometry • In low pT (~<2 GeV/c) • Pressure gradient of early stage • Hydrodynamical picture is established • In high pT (>~2 GeV/c) • Energy loss in dense medium (Jet Quenching) • Partonic flow(?) Here we focus on ellipticity of azimuthal momentum distribution, v2 (second Fourier coefficient) 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 (p0gg) • BBCs and ZDCs • Collision centrality determination • BBCs • Reaction plane determination and • Its resolution correction Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

  4. BBC in PHENIX South North ⊿η = 3.1 ~ 4.0 ⊿φ = 2π 144.35 cm • inner ring • middlering • outer ring BBC 64 elements Quartz Cherenkov radiator meshed dynode PMT 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 cm3 (18 X0) • 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 Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

  6. Method of p0 v2 Measurement • Define reaction plane by charged multiplicity on Beam-Beam Counters • p0 reconstruction from gamma measured by Electro-Magnetic Calorimeter (EMC) • For each pT, azimuthal angle, centrality • Combine both information • Counting number of p0 as a function of event anisotropy parameter measured reaction plane angle azimuthal angle of the particle vnreal = vnmeasured/ (reaction plane resolution)n Note: the detail of reaction plane definition will be found in nucl-ex/0305013 Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

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

  8. p0 Identification • Requirement for photon • Dead and noisy EMC towers are removed for the analysis • Energy of shower on EMC>0.040 [GeV] • PID cuts: c2<3 for photon probability • |TOF|<1.2 [ns] • Note: those cut are loser than single pT distribution analysis • For p0 • Asymmetry cut: |E1–E2| / ( E1+E2) < 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 ±p Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

  9. Example Plots from the Analysis Procedure After subtraction, there is 2nd component of B.G. in pT<2GeV/c region shape assumed as linear+asym. Gauss mgg [GeV/c2] count number of p0 in a range after 2nd B.G. subtraction (not used the fit function) Fit function: (average of p0 count)  ( 1 + 2 v2 cos[2(f - FR)]) Green lines : deviation by error of v2 f-FR [rad] Invariant mass of gg from same event and mixed event (classed by reaction plane, centrality, vertex position) 200GeV Au+Au normalization range for combinatorial B.G. subtraction mgg [GeV/c2] Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

  10. One of difficulties (?) is.. • The analysis of p0 v2 • Counting number of p0 as a function of centrality, pT and f-FR • The analyses (fitting of combinatorial background, its subtraction, counting p0 and so on) are done by macro automatically • However, we need to think it is not perfect, that is, it may fail sometime • Therefore, .... Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

  11. Toooooooooo many histograms checked by eyes Example of invariant mass distributions for each pT, f-FR in a centrality bin p0 as a function of f-FRb Before combinatorial background subtraction After combinatorial background subtraction Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

  12. v2 vs. pT vs. Centrality from 200GeV Au+Au phenix preliminary Statistical error is shown by error bar Systematic error from p0 count method and reaction plane determination is shown by gray box Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

  13. v2 vs. pT vs. Centrality from 200GeV Au+Au Charged p+K v2 consistent with p0v2 in pT<4GeV/c phenix preliminary }nucl-ex/0305013 Statistical error is shown by error bar Systematic error from p0 count method and reaction plane determination is shown by gray box The charged p and K v2 are shown only with statistical errors Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

  14. v2 vs. pT (Minimum Bias) from 200GeV Au+Au phenix preliminary • Identified particle v2 up to pT=10GeV/c 36.3106 [events] = 5.3+0.5-0.4 [(mb)-1] Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

  15. v2 vs. pT (Minimum Bias) from 200GeV Au+Au phenix preliminary }nucl-ex/0305013 • Identified particle v2 up to pT=10GeV/c 36.3106 [events] = 5.3+0.5-0.4 [(mb)-1] Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

  16. v2 vs. pT (Minimum Bias) from 200GeV Au+Au phenix preliminary nucl-ex/0305013 • Identified particle v2 up to pT=10GeV/c 36.3106 [events] = 5.3+0.5-0.4 [(mb)-1] Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

  17. Comparison with K0S and L (STAR) STAR data from nucl-ex/0306008 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 pT/nquark 1-3GeV/c • But we need more statistics to conclude it Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

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

  20. Comparison with a model phenix preliminary Special thanks to C. Nonaka (one of authors) of nucl-th/0306027 for data of model calculation 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 pT region. Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

  21. Summary • First measurement of p0 v2 at RHIC • In pT=1-10 GeV/c • v2 of the highest pT from identified particle • Charged p v2 consistent with p0v2 • In pT=1-3GeV/c • Minimum bias data shows finitep0v2 • Up topT~8 GeV/c • Special thanks to LBL and STAR people, especially Art Poskanzer • I learned all of event anisotropy analysis when I was here Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

  22. Outlook • Feature plan of analysis • Using high pT gamma trigger in run2 Au+Au data • We will have about twice statistics in high pT • need to study trigger bias • therefore, present analysis results are from minimum bias trigger events • h v2 is also available by same method • PHENIX has photon v2 also (STAR also, but not opened yet) • photon v2, especially low pT! • RHIC run4 Au+Au, it will be • Much more statistics • Detail study of v2 shape around pT=2-4GeV/c • Much higher pT • We want to know where is the end of finite v2 in very high pT 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 v2 for all of possible particles with large statistics • Already tried • charged p,K,p, deuteron, p0, e+(-) (inclusive), gamma (inclusive) • On going but need much more statistics • eta • direct gamma • inclusive gamma – [contribution from p0, eta (dominantly)] • charm and bottom meson • inclusive e+(-) – [contribution from p0 and eta dalitz decay (dominantly)] • Seems to be hard work, but... • K0s • Lambda • resonances • penta-quark • v1 on BBC (h=3-4) • Correlation method for vn • Cross section and HBT radii in-plane and out-plane Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

  24. Electron and Positron v2 PHENIX preliminary 200 GeV Au+Au Min. Bias v2 From talk of Singo Sakai (Ph.D student at Tsukuba Univ.) at JPS autumn meeting 2003 and DNP2003 pT[GeV/c] Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

  25. Photon v2 PHENIX preliminary STAR from my analysis (not finished...) 200 GeV Au+Au Min. Bias v2 pT [GeV/c] • From DNP2003 talk • Saskia Mioduszewski, • Edouard Kistenev, and • ShinIchi Esumi Masashi Kaneta, RBRC, BNL Heavy Ion Tea in Nuclear Science Division, LBNL (2003/11/5)

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