High p T identified hadron anisotropic flow and Deuteron production in 200 GeV Au+Au Collisions Shengli Huang Vanderbilt University for the PHENIX Collaboration for the PHENIX Collaboration

S.L. Huang WWND08 2  Observables and Motivation  Analysis methods  Results and Discussion ,K,p(pbar) v 2, v 4 Deuteron production(dbar/d, R CP, B 2 …)  Conclusions Outline:

Anisotropic flow v 2 and v S.L. Huang WWND08 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

S.L. Huang WWND08 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  How about the higher order anisotropic flow such as v 4 ?  Where is the break point where the hydro interfaces with jet fragmentation baryon meson

S.L. Huang WWND08 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

S.L. Huang WWND086 Recombination module Large baryon/meson ratios, a factor of 3 above standard fragmentation The data prefer to the particle production by the recombination in the intermediate p T The deuteron will supply more information to check the recombination module

S.L. Huang WWND087 PHENIX in Run 7 Run 7:  ~5.5B 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

S.L. Huang WWND08 8 TOFw and Aerogel Detectors 1.TOFw intrinsic timing resolution is ~ 75ps 2.  /K can be separated to 2.8 GeV/c, K/p can be separated to 4.5 GeV/c and deuteron can be identified to 6~7GeV/c 3. Together with Aerogel detector(ACC), we can identify the K to p T ~4 GeV/c and , p to 7 GeV/c

S.L. Huang WWND08 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

S.L. Huang WWND08 10 The mass ordering has also been observed for v 4 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 A.Taranenko

S.L. Huang WWND08 11 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?

S.L. Huang QM08 12 Perfect Partonic Liquid b) Partons in different momentum space also can recombine with each other Partons just in similar momentum space can recombine with each other Meson Baryon L.W. Chen, C.M. Ko nucl-th Mesons and baryons have equal v 4 /(v 2 ) 2 a) Perfect Partonic Liquid!

S.L. Huang WWND08 13 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!

S.L. Huang WWND08 14 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

S.L. Huang WWND08 15 Break Point?  In the centrality of 20~60%, the , K and p KE T scaling seemingly begins to break at KE T /nq ~ 1 GeV  More statistics are required for the further investigation KE T /nq(GeV)

16 Deuteron p T Spectra The deuteron and anti-deuteron yield have been measured to p T ~ 5 GeV/c in difference centrality H. Valle QM S.L. Huang WWND08

17 dbar/d ratio vs p T Similar to pbar/p ratio, no p T and centrality dependence has been observed for the dbar/d ratio The dbar/d ratio is 0.46±0.01(stat)±0.05(sys) and p/bar is 0.73 ± 0.01 The dbar/d ratio is close to the (pbar/p) S.L. Huang WWND08

18 The deuteron R CP peaks at p T ~3~3.5GeV/c with the value around 2.8 Deuterons R cp S.L. Huang WWND08

19 Coalescence Parameter B 2  The B 2 of d and dbar as a function of p T in difference centrality  B 2 increases from central to peripheral collisions  B 2 rises with p T p d = 2p p S.L. Huang WWND08

20 B 2 and System Volume Significant change in B 2 from 14.5 to 60 N part 1/B 2 vs N part shows a consistent linear rise S.L. Huang WWND08

21 Centrality dependence of Source size Radii shows linear increase as the cubic root of the number of participants (N part ) Consistent with HBT radii for pions. Phys.Rev.Lett.93, (2004) S.L. Huang WWND08

S.L. Huang WWND08 22 Conclusions New time of flight detector(TOFw) of PHENIX runs successfully in Run 7 with 75 ps intrinsic timing resolution. With new TOFw, we have measured the identified charged hadrons v 2 to p T ~6 GeV/c, v 4 to 4GeV/c and deuteron spectra to 5GeV/c The number of constituent quark scaling seemingly begins to break for v 2 as KE T /nq~1GeV at 20~60% centrality The d/dbar ratio has no p T and centrality dependence and the deuteron R cp peaks at p T ~3~3.5GeV/c with the value around 2.8 The coalescence parameter (B 2 ) and source radius extracted from deuteron production indicate that the source radius decreases with p T but increases linearly with N part 1/3, which is consistent with expanding source 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