Azimuthal Anisotropy and the QGP Yasuo MIAKE, Univ. of Tsukuba i)Why I Iike azimuthal anisotropy ii)Tsukuba strategy for RHIC-PHENIX iii)What is found at RHIC

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, Reasons why I love azimuthal anisotropy Info. on mean free path vs. R Clear origin of the signal ! Geometry is clear observable Conversion of eccentricity to v 2 Anisotropy of the coordinate space converted to that of the momentum space. Centrailty dependence/different collision(AuAu vs CuCu) gives good tests Reaction Plane Almond shape

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, Sensitivity to the early stage Anisotropy in coordinate space disappears quickly Ratio of eccentricity after a time delay Disappears quickly  v 2 senses early stage of collision RQMDKolb et.al., PRC62(2000) Time

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, BBC Central arm beam 0-5% 5-10% 10-20% BBC Key1; reliable R.P. determination Wide rapidity gap from central detector Free from other source of corr such as HBT, decays, jets & auto-corr. Corr. between SMD(spect) and BBC(part) also confirmed → R.P. determination from whole event wide

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, PHENIX Preliminary Proton K+K+ K-K- ++ -- p e+ e+ e- e- Key2; PID with TOF & Aerogel High resolution TOF and low index of 1.01 Aerogel Cherenkov Both Tsukuba contribution 385cm 200cm

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, What we expected before RHIC There is a tendency of saturation!? Hadron cascade predicts a few %.

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, Surprise ! Early compilation AGS SPS RHIC

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, Large azimuthal anisotropy Larger in higher energies. Increase with pt and saturate PHOBOS; nucl-ex/ Phenix; P.R.L. 94, (2005) Central Peripheral

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, Failure of hadronic scenarios Hadronic cascade calculation found to underestimate v 2 at RHIC. v 2 ~ % Mean free path is shorter than that from hadronic rescatternings. System thermalized early with the mechanism other than hadronic rescatterings. M. Bleicher, H. Stocker Phys. Lett. B526 (2003) 309

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, v 2 vs. Eccentricity At low pt region, the ratio stays ~constant Eccentricity scaling observed in comparison of Au+Au, Cu+Cu  Scaling with eccentricity shows v 2 builds up at early stage Phenix; PRL 89(2002)212301

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, v 2 with particle identification Low pt region; v2(  ) > v2(K) > v2(p) Mass Ordering Good agreement with hydrodynamics Very early thermalization (0.6 fm/c) & high energy density (~20 GeV/fm 3 ) required !   More from Hirano’s talk Perfect fluid (low viscous) What brings the system thermalization in such a short time!   Partonic degree of freedom Deviations at high pt region (> 1.5 GeV/c); v2( ,K) < v2(p) Other mechanism? PHENIX : P.R.L. 91, (2003) PHENIX Preliminary : Extended PID

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, Mass Ordering in single spectra Exponential in mt for low pt region Known from AGS & SPS era Mass ordering of slope parameters Proof of hydrodynamical collective flow m t -m Collective Flow PHENIX, PRC69,034909(2004)Au+Au at 200 GeV/n

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, Other surprise; baryon dominance We had many reasons to consider > 2GeV/c is the jet region. In peripheral, p/  ratio similar to those in ee/pp suggesting fragmentaton process. Fragmentation process should show n p < n  as seen in ee/pp. In central Au+Au, p/  ratio increases with centrality, suggesting other mechanism. Phenix; P.R.L. 91(2003)  Quark Recombination Model (Quark Coalescence Model)  High resolution Time-of flight detector

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, Quark coalescence model (RECO) Quarks, anti-quarks combine to form mesons and baryons from universal quark distribution, w(pt). QGP Hadron Mom. distr. of meson (2q) ； Mom. distr. of baryon (3q) ； w(pt) ； Universal mom. distr. of quarks ｛ steep in p t ｝ Because of the steep distr. of w(pt), RECO wins at high pt even w. small Cx. Characteristic scaling features expected.  Quark number scaling

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, Proton dominance by RECO Recombination model explains the proton dominance.

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, QGP Hadron V 2 from RECO Characteristic scaling behavior Azimuthal distr of quark; w Azimutal distr. of meson (2q) ； Azimuthal distr. of baryon (3q) ；

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, Quark number scaling observed! Quark number scaling clearly observed in v 2. Distinct difference between Baryon Meson also seen in R CP, yield ratio of central and peripheral coll. Presented by M. Lamont (QM04) Baryon Meson

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, KE T = m T – m Mass ordering of quarks? WWND 2006, M. Issah Accidental OR ordering in mass of quarks? Existence of hypersurface where QGP converted to hadrons? Kinetic energy of constituent quarks

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, Study of electron for charm  conversion  0   ee    ee, 3  0   ee,  0 ee   ee,  ee   ee  ’   ee Origins of electrons “photonic” Dalitz decays of  Photon conversions “non-photonic” Semi-leptonic decays of heavy flavored mesons  Electron yields are consistent with those photonic + charm decays.

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, Charm v 2 from electrons Measure v 2 of inclusive electrons Evaluate contribution of photonic electron Cocktail Method Converter Method Then, subtract ! measured evaluated knownobtained! inclusive e v 2 (w.o. converter) photonic e v 2 S.Esumi & S.

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, Charm seems to flow! V 2 of the non- photonic electron, mostly charm contribution at low pt Data seem to favor the flow of the charm. If so, thermalized & flowing charm supports quark- coalescence & formation of QGP. V.Greco, C.M.Ko, R.Rapp,PLB595(2004)202. S.Esumi & S.

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, Study of direct photon Measure v 2 of inclusive photon and  0 ’s. Subtract hadronic decays ( , , etc) from the inclusive v2, direct photon! Direct photons are from compton-like “prompt” process? v2v2 R; direct photon excess ratio v2v2 PHENIX, PRL 96,032302(2006)

Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, Summary of my talk v 2 is fun! Establishment of R.P. is great ! v 2 is even useful ! Thermalization as early as 0.6 fm/c Large azimuthal anisotropy cannot be generated with hadronic process. Support the quark recombination model Collectivity at parton level Phenomenological, but universal quark distribution function!  statistical description of quarks  QGP Much fun to come Charm & photon ! New text book for graduate students