1. Azimuthal anisotropy measurement of neutral pion and direct photon in  s NN =200GeV Au+Au collisions at RHIC-PHENIX TAC seminar 11/25/2008 Kentaro MIKI Univ. of Tsukuba mail to: kentaro@rcf2.rhic.bnl.gov

2. 11 / 25 / 2008Kentaro Miki2 1. Introduction 2. Physics Motivation 3. Experiment 4. Data Reduction 5. Data Analysis 6. Result / Discussion 7. Conclusion / Summary - Quark Gluon Plasma - Electro Magnetic Particle - Physic result at RHIC

3. 11 / 25 / 2008Kentaro Miki3 1-1. Quark Gluon Plasma Quark Gluon Plasma -> The quark and the gluon move freely in a large volume. -> QGP formed under high temperature and energy density. Is there an end in the size of the matter? Heavy Ion Collision Experiment -> High temperature and high density necessary for generating QGP is produced by the high energy heavy ion collisions.

4. 11 / 25 / 2008Kentaro Miki4 1-2. Heavy Ion Collision Experiment In order to provide the QGP state on the ground, Au nucleus is collided at  s NN = 200 GeV by the Relativistic Heavy Ion Collider at BNL. Critical temperature / energy density by Lattice QCD T c ~ 170 MeV  c ~ 1.2 GeV/fm 3

5. 11 / 25 / 2008Kentaro Miki5 1-3. Electro Magnetic Particles Electro magnetic particles are the powerful probes to the study property of QGP since they do not interaction strongly with any other particles and thus can carry out information on the states where they are emitted. Photons are emitted from all stage of collisions. Cartoon from Dinesh K. Srivastava, Quark Matter 2008

6. 11 / 25 / 2008Kentaro Miki6 1-4. Production Process Annihilation + Compton fragment Direct photon production process in p+p collisions process1 (Annihilation + Compton Scattering) process2 (Fragmentation) Isolated direct photon cut : 0.1*E  > Econe(R=0.5) Isolation cut can reduce the bremmstrahlung photons parton distribution function (PDF)process1process2fragmentation function (PDF)

7. 11 / 25 / 2008Kentaro Miki7 1-5. Ratio of Photons QGP-ThermalJet-photon NLO-pQCD All High p T direct photons are well described by NLO-pQCD calculation. Phys. Rev., C69:014903(2004) thermal window -> 1~3 GeV/c prompt photon window -> 6~ GeV/c High p T direct photons are produced in the initial stage. Thermal radiation are emitted in the low p T region.

8. 11 / 25 / 2008Kentaro Miki8 1-6. High p T Direct Photon Yield NLO-pQCD calculation well described the photon data of p+p collisions in the world experiment. Blue line: Ncoll scaled p+p cross section High p T Photon yield in Au+Au is also well explained by NLO-pQCD.

9. 11 / 25 / 2008Kentaro Miki9 1-7. Nuclear Modification Factor Non jet quench on the Direct photon Probe of isospin effect in high p T ? p T scaled by 62.4/200 (x T scaling inspired) -> difference of quark charge between neutrons and photons -> yield of photons from p+p, p+n and n+n should have different value. -> The difference of photon yield from Au+Au and p+p would be appeared in R AA of direct photon.

10. 11 / 25 / 2008Kentaro Miki10 1-8. Direct Photon History log t pTpT 11010 7 (GeV) hadron decays hadron gas sQGP hard scatter jet Brems. jet-thermal jet fragmentation Cartoon from G. David, Hard Probe 2006 Photons emitted from all stage in the history of hot dense medium. How distinguish one photon from all emissions?

11. 11 / 25 / 2008Kentaro Miki11 2. Physics Motivation 1. Introduction 2. Physics Motivation 3. Experiment 4. Data Reduction 5. Data Analysis 6. Result / Discussion 7. Conclusion / Summary - Azimuthal Anisotropy - Prediction of Photon v 2 - My Activity

12. 11 / 25 / 2008Kentaro Miki12 2-1. Azimuthal Anisotropy  : azimuthal angle of particles  : azimuthal angle of reaction plane -Elliptic flow (v 2 ) is defined by the 2nd coefficient of Fourier expansion The collision participation part in the early stage has spatial anisotropy. Pressure gradient is the largest in the shortest direction of the ellipsoid. Emitted particles reflect initial spatial anisotropy.

13. 11 / 25 / 2008Kentaro Miki13 2-2. Emission Processes Photons are emitted from all stage of heavy ion collisions! Hard Scattered sQGP Thermal Jet Fragmentation Hadron Decay Jet Bremmstrahlung

14. 11 / 25 / 2008Kentaro Miki14 2-3. Prediction Hard Scatter Jet Brems. Jet Fragment QGP v 2 = 0 v 2 < 0 v 2 > 0 v 2 ≥ 0 annihilation compton scattering Bremsstrahlung (energy loss) v 2 > 0 v 2 < 0 Photon emission from jet Turbide, Gale, arXiv:0712.0732 The sign of v 2 depending on the production processes of photons. v 2 is a powerful tool to explore the source of direct photons.

15. 11 / 25 / 2008Kentaro Miki15 2-4. My Activity 2006 2007 2008 01.08 RHIC-AGS meeting 03.27 JPA -spring- BNL 09.21 JPA -fall- 11.16-20 QM2006 in Shanghai 11.24 International workshop in Xi’an BNL 04.01 Junior Research Associate 02.08 QM2008 in India 11.01 start up RHIC Run8 BNL Centrality calibration for Run7 preliminary request for pi0 v2 in Run7 preliminary request for direct photon v2 in Run4 TOF calibration for Run6

16. 11 / 25 / 2008Kentaro Miki16 3. Experiment 1. Introduction 2. Physics Motivation 3. Experiment 4. Data Reduction 5. Data Analysis 6. Result / Discussion 7. Conclusion / Summary - Relativistic Heavy Ion Collider - the Pioneering High Energy Nuclear Interaction eXperiment

17. 11 / 25 / 2008Kentaro Miki17 3-1. RHIC Accelerators Tandem Van de Graaff Linear Accelerator Booster Synchrotron Alternating Gradient Synchrotron Relativistic Heavy Ion Collider Experiments PHENIX, STAR, BRAHMS, PHOBOS

18. 11 / 25 / 2008Kentaro Miki18 3-2. PHENIX Detectors lead scintillator (PbSc) ・ energy resolution 2.1  8.1 %/ E 1/2 [GeV] lead glass (PbGl) ・ energy resolution 0.76  5.95 %/ E 1/2 [GeV] Reaction Plane Detector 1.0 < |  | < 2.8 16 sectors in each side Beam-Beam counter event trigger reaction plane determination

19. 11 / 25 / 2008Kentaro Miki19 4. Data Reduction 1. Introduction 2. Physics Motivation 3. Experiment 4. Data Reduction 5. Data Analysis 6. Result / Discussion 7. Conclusion / Summary - Photon Identify - Calibrations

20. 11 / 25 / 2008Kentaro Miki20 4-1. Photon Identify 1. Cluster 2. Peak area 3. EMCal shower

21. 11 / 25 / 2008Kentaro Miki21 4-2. Calibration ~Centrality~ The centrality is determined by the correlation of BBC charge sum and ZDC energy in PHENIX. The boundaries of centralities are calibrated to make flat the centrality distribution.

22. 11 / 25 / 2008Kentaro Miki22 4-3. Calibration ~Reaction Plane~

23. 11 / 25 / 2008Kentaro Miki23 5. Data Analysis 1. Introduction 2. Physics Motivation 3. Experiment 4. Data Reduction 5. Data Analysis 6. Result / Discussion 7. Conclusion / Summary - Inclusive Photon -  0 - Hadron Decay by Simulation - Direct Photon

24. 11 / 25 / 2008Kentaro Miki24 5-1. Data analysis Direct  hadron decay  Inclusive photon 00 ’’ 2 nd harmonic amplitude : v 2

25. 11 / 25 / 2008Kentaro Miki25 5-2. Inclusive photon Event / Cluster cut : BBC vertex < 30 cm ZDCNS > 1 Centrality defined by BBC only Reaction plane defined by RxNP emc Cluster energy > 0.2 GeV pc3 rejection cut > 6.5 cm Centrality : 0-92% (10% step) pT range : 1.0 - 16.0 [GeV/c] Data Set : Au+Au 200 GeV Run4 (~800M events) Run7 (~4.0G events)

26. 11 / 25 / 2008Kentaro Miki26 5-3. Inclusive photon v 2 (Run7) Fitting Function

27. 11 / 25 / 2008Kentaro Miki27 5-4. Invariant mass distribution of  0 Invariant mass distribution of 2  dN / dphi distribution of pi0 Basically, same cut with inclusive photon analysis. Combinatrial back ground is estimated by event mix distribution.

28. 11 / 25 / 2008Kentaro Miki28 5-5.  0 raw yield Filled circle :  0 raw yield Opened circle :  0 yield at Run4 PHENIX preliminary Au+Au 200 GeV

29. 11 / 25 / 2008Kentaro Miki29 5-6. Hadron decay contamination Since components other than  0 cannot be measure directly, the hadron decay contamination is estimated by using Monte-Carlo.

30. 11 / 25 / 2008Kentaro Miki30 5-7. Hadron decay photon v 2 Hadron decay photon v 2 is estimated by Exodus using m T scaled  0 v 2. point-to-point fitting above 5 GeV m T scaled v 2 for Exodus input up/down line : sys. error from  0 statistical error Decay photon v 2 from each parent particles.

31. 11 / 25 / 2008Kentaro Miki31 5-8. Cocktail above 3GeV,  0 77.6 %  19.0 %  3.7 %  0.5 %  ’ 2.0 % Parent spectra from Exodus output. Red point is measured data of  0 (PPG080).  0 output is normalized by data. other hadrons are normalized by  0 and their decay ratio. Cocktailed the decay photons v 2 according to contamination ratio.

32. 11 / 25 / 2008Kentaro Miki32 5-9. Direct photon v2

33. 11 / 25 / 2008Kentaro Miki33 6. Result / Discussion 1. Introduction 2. Physics Motivation 3. Experiment 4. Data Reduction 5. Data Analysis 6. Result / Discussion 7. Conclusion / Summary

34. 11 / 25 / 2008Kentaro Miki34 6-1. Run4 Result Inclusive / Hadron Decay / Direct photon v 2 in Run4 200GeV Au+Au - Photon v 2 is measured up to 10GeV/c. - Consistent with zero.

35. 11 / 25 / 2008Kentaro Miki35 6-2. Run7 Inclusive Photon Inclusive Photon v 2 in Run7 by using RxNP - Measured 10% and 20% steps of centrality. - Extended up to 16.0 GeV/c

36. 11 / 25 / 2008Kentaro Miki36 6-3. Run7  0 v 2  0 v 2 is estimated by using RxNP in Run7 up to 16.0 [GeV/c]. - Measured 10% and 20% steps of centrality. - Extended up to 16.0 GeV/c

37. 11 / 25 / 2008Kentaro Miki37 6-4. Comparison with Hadrons The  0 v 2 compared with charged hadron v 2. -  0 v 2 is good agreement with pion v 2 (Run4). - There is un-consistency between the result from RxNP and BBC above 4GeV/c.

38. 11 / 25 / 2008Kentaro Miki38 6-5. Hadron Decay Photon v 2 Inclusive Photon v 2 and Hadron Decay Photon v 2 in Run7 by using RxNP - Significant different is appeared between Inclusive and hadron decay in high p T. - The systematic error on hadron decay is propagated from statistical and systematic error of  0.

39. 11 / 25 / 2008Kentaro Miki39 6-6. Direct Photon v 2 Direct Photon v 2 in Run7 by using RxNP - extended up to 16GeV/c - run4 double ratio is used - Non-Zero v 2 about 3GeV ? - Centrality dependence annihilation compton scattering Bremsstrahlung (energy loss) v 2 > 0 v 2 < 0

40. 11 / 25 / 2008Kentaro Miki40 6-7. Comparison with the result by BBC. Reaction Plane angle is defined by RxNP Reaction Plane angle is defined by BBC Central Arm |  | < 0.35 BBC 3.0 < |eta| < 3.9 RxNP 1.0 < |eta| < 2.8 

41. 11 / 25 / 2008Kentaro Miki41 6-8. Comparison with Theoretical Prediction RxNP BBC arXiv:0712.0732v2

42. 11 / 25 / 2008Kentaro Miki42 6-9. Comparison with R AA In the 2~4 GeV/c region, 1. Enhancement of direct photon in Au+Au 2. Direct photon v 2 might be non-zero => There is other components ??

43. 11 / 25 / 2008Kentaro Miki43 6-10. Additional Analysis > Direct photon v 2 in Run7 still has large error bar… Estimation of thermal photon from virtual gamma analysis How to improve the Direct photon v2 result in low pT region?

44. 11 / 25 / 2008Kentaro Miki44 6-11. Virtual Photon Analysis ÷ ÷ ÷ 0-30 90-140 140-200 200-300 R data Kroll-Wada Formula

45. 11 / 25 / 2008Kentaro Miki45 6-12. Thermal Photon Spectra  (inclusive) =  (decay) +  (direct) Double ratio: (  incl /  0 ) measured / (  decay/  0 ) background =  incl /  decay =1+  direct /  decay Compare to NLO pQCD (p+p consistent with pQCD) Compare to thermal model D. d’Enterria, D. Peressounko (nucl-th/0503054) 2+1 hydro T 0 ave =360 MeV (T 0 max =570 MeV)  0=0.15 fm/c Data consistent with thermal + pQCD

46. 11 / 25 / 2008Kentaro Miki46 6-13. Thermal Photon v 2 ?? RxNP - Improved below 3GeV/c - Ordinary method should be used above 4GeV/c RxNP BBC

47. 11 / 25 / 2008Kentaro Miki47 6-14. Thermal Photon v 2 Comparison the final result with direct photon prediction. - Photon v 2 is larger than theoretical curve. - Need to check the calculation model. - Need to check with the discussion of hadron analysis.

48. 11 / 25 / 2008Kentaro Miki48 7-1. Conclusion -  0 and inclusive photon v 2 is very effective probe to study the high p T region. - Direct photon seems to have non-zero v 2 above 3GeV/c. - The influence of jet (or jet-suppression) is appeared even direct photon. - Virtual photon analysis is effective in low p T region. - Thermal photon v 2 is larger than theoretical prediction curve described in arXiv:0712.0732v2. - Need to more physics study with charged hadron analysis or several models.

49. 11 / 25 / 2008Kentaro Miki49 7-2. Summary - Estimated inclusive /  0 / hadron decay photon v 2 at 10% steps and 20% steps up to 60% and minimum bias. - direct photon v 2 measured using RxNP or BBC. - estimated the low p T direct photon v 2 by using the double ratio which is calculated in the thermal photon analysis. - Extended p T range up to 16 GeV/c - Improved v 2 accuracy below 3 GeV/c Tasks… - Applying new energy calibration. - Systematic error study of remaining hadrons on the inclusive photon - Comparison with charged hadron data and several models.

50. 11 / 25 / 2008Kentaro Miki50 Ex Back up

51. 11 / 25 / 2008Kentaro Miki51 Ex. Systematical uncertainty Systematical error on the inclusive photon v 2 is estimated from 4 sources. 1. PID photon identification cut ON/OFF 2. Method dN / dphi vs average cosine 3. Reaction Plane Estimated by BBC in Run2 4. Hadrons Remaining hadrons contamination after photon cut

52. 11 / 25 / 2008Kentaro Miki52 Ex. Double Ratio

53. 11 / 25 / 2008Kentaro Miki53 Q=p T /sqrt(2) for prompt calculations, Turbide et al. (see also Arleo, JHEP 0609, 015 (2006), Liu & Werner, hep-ph/0712.3619 and Liu & Fries, nucl-th/0801.0453. ).