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Azimuthal Anisotropy and the QGP

Azimuthal Anisotropy and the QGP. Yasuo MIAKE, Univ. of Tsukuba. Why I Iike azimuthal anisotropy Tsukuba strategy for RHIC-PHENIX What is found at RHIC. Reaction Plane. Almond shape. Reasons why I love azimuthal anisotropy. Info. on mean free path  vs. R

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Azimuthal Anisotropy and the QGP

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

  2. Reaction Plane Almond shape Reasons why I love azimuthal anisotropy • Info. on mean free path  vs. R • Anisotropy of the coordinate space converted to that of the momentum space. • Clear origin of the signal ! • Geometry is clear • From eccentricity to v2 • Centrailty dependence gives good tests • Sensitivity to the early stage of collisions ! Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006

  3. Sensitivity to the early stage RQMD Kolb et.al., PRC62(2000)054909 • Anisotropy in coordinate space disappears quickly • Ratio of eccentricity after a time delay • Disappears quickly •  v2 senses early stage of collision Time Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006

  4. 0-5% 5-10% 10-20% beam BBC BBC Central arm 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, 2006

  5. e+ p+ PHENIX Preliminary K+ Proton 385cm p K- 200cm p- e- 200cm Key2; PID with TOF & Aerogel • High resolution TOF and low index of 1.01 Aerogel Cherenkov • Both Tsukuba contribution Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006

  6. 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, 2006

  7. RHIC SPS AGS Surprise ! • Early compilation Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006

  8. Phenix; P.R.L. 94, 232302(2005) Central Peripheral Large azimuthal anisotropy • Larger in higher energies. • Increase with pt and saturate PHOBOS; nucl-ex/0406021 Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006

  9. Failure of hadronic scenarios • Hadronic scenario underestimates v2 at RHIC. • v2 ~ 1 - 2 % • 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, 2006

  10. v2 vs. Eccentricity Phenix; PRL 89(2002)212301 • At low pt region, the ratio stays ~constant • Eccentricity scaling observed in comparison of Au+Au, Cu+Cu • Scaling with eccentricity shows v2 builds up at early stage Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006

  11. v2 with particle identification PHENIX : P.R.L. 91, 182301 (2003) • 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/fm3) 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) • Meson vs Baryon? • Other mechanism? PHENIX Preliminary : Masui@QM05 Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006

  12. mt-m Mass Ordering in single spectra Au+Au at 200 GeV/n PHENIX, PRC69,034909(2004) • Exponential in mt for low pt region • Known from AGS & SPS era • Mass ordering of slope parameters • Proof of hydrodynamical collective flow Collective Flow Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006

  13. 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 np < n as seen in ee/pp. • In central Au+Au, p/ ratio increases with centrality, suggesting other mechanism. Phenix; P.R.L. 91(2003)172301  High resolution Time-of flight detector  Quark Recombination Model (Quark Coalescence Model) Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006

  14. Hadron Mom. distr. of meson (2q)； Mom. distr. of baryon (3q)； w(pt)； Universal mom. distr. of quarks ｛steep in pt｝ QGP Quark recombination model (RECO) • Quarks, anti-quarks combine to form mesons and baryons from universal quark distribution, w(pt). • Characteristic scaling features expected. • Quark number scaling Because of the steep distr. of w(pt),RECO wins at high pt even w. small Cx. Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006

  15. Proton dominance by RECO • Recombination model explains the proton dominance. Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006

  16. Hadron QGP V2 from RECO • Characteristic scaling behavior Azimutal distr. of meson (2q)； Azimuthal distr. of baryon (3q)； Azimuthal distr of quark; w Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006

  17. Presented by M. Lamont (QM04) Baryon Meson Quark number scaling observed! • Quark number scaling clearly observed in v2. • Distinct difference between Baryon Meson also seen in RCP, yield ratio of central and peripheral coll. Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006

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

  19. gconversion p0 gee h gee, 3p0 w ee, p0ee f ee, hee r ee h’  gee Study of electron for charm • 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, 2006

  20. photonic e v2 inclusive e v2 (w.o. converter) measured evaluated known obtained! Charm v2 from electrons S.Esumi & S. Sakai@SQM2006 • Measure v2 of inclusive electrons • Evaluate contribution of photonic electron • Cocktail Method • Converter Method • Then, subtract ! Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006

  21. Charm seems to flow! S.Esumi & S. Sakai@SQM2006 • 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. Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006

  22. v2 v2 0.2 0.2 0.1 0.1 0.0 0.0 Study of direct photon PHENIX, PRL 96,032302(2006) • Pi-zero results consistent with other mesons • No significant diff. btwn inclusive v2 and expected photon v2 from hadronic decay (pion, eta, etc) • Direct photons are from compton-like “prompt” process? R; direct photon excess ratio Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006

  23. Summary of my talk • v2 is fun! • Establishment of R.P. is great ! • v2 is even useful ! • Sensitive to the early stage of collisions • 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 Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006

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