High p T identified charged hadron v 2 and v 4 in 200GeV AuAu collisions by the PHENIX experiment Shengli Huang Vanderbilt University for the PHENIX Collaboration for the PHENIX Collaboration

S.L. Huang QM08 2  Observables and Motivation  Analysis methods  Results and Discussion  Conclusions Outline:

Anisotropic flow v 2 and v S.L. Huang QM08 3 x y beam reaction plane Peter Kolb, PRC 68,  Azimuthal correlation with the reaction plane  Built up in the early stage and self-quenched, therefore supply the early information of matter generated in the collision Spatial space asymmetry momentum space asymmetry

SL Huang QM08 4 Partonic Flow PHENIX, PRL. 99, (2007) PRL. 99, (2007) Baryon and meson elliptic flow follow the number of constituent quark scaling as a function of KE T. This indicates that partonic flow builds up at RHIC  Where is the break point where the hydro interfaces with jet fragmentation The medium density and strength of interactions  The dynamic range of the global partonic flow  How about the higher order anisotropic flow such as v 4 ? baryon meson

S.L. Huang QM08 5 Star Preliminary V 4 /(v 2 ) 2 ratio v 4 /v 2 2 is a probe of ideal hydro behavior and related to the degree of thermalization! Peter Kolb, PRC 68, R.S.Bhalerao et.al PLB 627,49; Borghini and Ollitrault, PLB642,227 Hydro dynamics predicts v 4 /v 2 2 ~0.5 The identified particles v 4 /v 2 2 ratio should provide more detailed information than that of charged hadron Y.T. Bai QM06

SL Huang QM08 6 How to Coalesce? a) Similar momentum space b) Different momentum space Meson Baryon Meson Baryon  The measurement of meson and baron v 4 /v 2 2 ratio will allow us to extract the partonic v 4,q /v 2,q 2 ratio  To test whether the partons in different momentum space also can recombine with each other L.W. Chen, C.M. Ko nucl-th  : modification factor

SL Huang QM087 PHENIX in Run 7 Run 7:  ~4.5B events and around 50% have been used  A new Time of Flight detector (TOFw) has been installed in the west arm of PHENIX  A new reaction plane detector (RxNP) has been installed in the 38 cm < |z| < 42 cm alone the beam

SL Huang QM08 8 TOFw and Aerogel Detectors 1.TOFw intrinsic timing resolution is ~ 75ps 2.  /K can be separated to 2.8 GeV/c and K/p can be separated to 4.5 GeV/c 3. Together with Aerogel detector(ACC), we can identify the K to p T ~4 GeV/c and , p to 7 GeV/c

SL Huang QM08 9 RxNP:  Two sets of plastic scintillators positioned on either side of the collision vertex  12 segments in   2 segments in  1.0 < |  | < < |  | < 2.8 BBC: 3.1<|  |<3.9  Both detectors are away from mid-rapidity. Smaller non-flow effect on the reaction plane measurements  New RxNP detector resolution is around 74% at mid-centrality Reaction plane Measurements Sqrt(2*cos(2*(  N -  S )))

S.L. Huang QM08 10 Mass ordering of v 2 and v 4  V 4 has been measured as a function of p T in different centrality bins for the , K and p  Mass ordering has been observed for both v 2 and v 4 Consistent with the hydrodynamics Poster 166 A.Taranenko

S.L. Huang QM08 11 The v 4 follows the KE T scaling well for KE T < 1 GeV The number of constituent quark scaling holds for v 4 when KE T /nq < 1 GeV. This confirms that matter with partonic degrees of freedom has been generated at RHIC KE T Scaling of v 4 P166 A.Taranenko

S.L. Huang QM08 12 V 4 /(v 2 ) 2 ratio The ratio of v 4 /(v 2 ) 2 is close to 0.9 for the , K and p Mesons and baryons have similar v 4 /(v 2 ) 2 ratio What can we extract from this measurement?

S.L. Huang QM08 13 Partonic Thermalization ! 1.Parton v 4,q /(v 2,q ) 2 ~0.5 Perfect Partonic Liquid! 2.Partons in different momentum space also can recombine with each other 3. Interact more frequently and strongly with each other

S.L. Huang QM08 14 Charged  v 2  Charged  v 2 can be measured to 6 GeV/c.  The results are consistent with  0 results in the overlap p T region.  All  v 2 start to drop at p T ~ 2.5 GeV/c in the different centrality bins!

SL Huang QM08 15 Kaon and Proton v 2  Kaon v 2 can be measured to 4 GeV/c and protons v 2 can be measured to 6 GeV/c  Proton v 2 starts to drop at p T ~ 4 GeV/c

SL Huang QM08 16 Break Point?  In the centrality of 20~60%, the , K and p KE T scaling seemly begins to break at KE T /nq ~ 1 GeV  More statistics are required for the further investigation A factor 2 of Run 7 data will come after QM08 KE T /nq(GeV)

SL Huang QM08 17 Conclusions New time of flight detector(TOFw) of PHENIX runs successfully in Run 7 with 75 ps intrinsic timing resolution. With new TOFw and RxNP detectors, we can measure the identified charged hadrons v 2 to p T ~6 GeV/c and v 4 to 3 GeV/c The number of constituent quark scaling has been observed for v 4 for KE T /nq < 1 GeV. Mesons and bayrons have similar v 4 /(v 2 ) 2 ratio which is close to 0.9 The parton v 4,q /(v 2,q ) 2 ~ 0.5 : perfect partonic liquid Partonic Thermalization The number of constituent quark scaling seemly begins to break for v 2 as KE T /nq~1GeV at 20~60% centrality: a)The interface between hydro and jet fragmentation b)Quantitative information about density and interaction strength