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Energy Scan of Hadron ( p 0 ) Suppression and Flow in Au+Au Collisions at PHENIX

Energy Scan of Hadron ( p 0 ) Suppression and Flow in Au+Au Collisions at PHENIX. Norbert Novitzky for PHENIX collaboration University of Jyväskylä, Finland Helsinki Institute of Physics, Finland. Outlook. Introduction Nuclear Modification Factor (R AA ) Flow measurement (v 2 )

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Energy Scan of Hadron ( p 0 ) Suppression and Flow in Au+Au Collisions at PHENIX

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  1. Energy Scan of Hadron (p0) Suppression and Flow in Au+Au Collisions at PHENIX Norbert Novitzky for PHENIX collaboration University of Jyväskylä, Finland Helsinki Institute of Physics, Finland Norbert Novitzky for PHENIX

  2. Outlook • Introduction • Nuclear Modification Factor (RAA) • Flow measurement (v2) • Low-energy scan: • Motivation • Global observables in energy scan • v2 results of p0 • Low-energy p+p and Au+Au spectra, xT scaling • RAAresults of p0 • Fractional energy loss studies in low-energy scan • Summary Norbert Novitzky for PHENIX

  3. p+p varies with impact parameter b Nuclear modification factor A+A Norbert Novitzky for PHENIX

  4. larger pressure gradient in plane thermalization Reaction Plane less yield out more in plane z y x Spatial asymmetryeccentricity Mom. Asymmetry elliptic flow Nuclear Geometryand Hydrodynamic flow RP Norbert Novitzky for PHENIX

  5. High pTv2versus RAA(Df,pT) What is the connection of measure v2 and RAA(Df,pT) at high pT? The RAA with respect to reaction plane: approximation where The connection between RAA and v2 : Norbert Novitzky for PHENIX

  6. Motivation – Suppression in low energy scan Phys. Rev. Lett.101, 162301 (2008) • Cu+Cu energy scan: • Centrality dependence of RAAat √sNN = 200 and 62.4 GeV • NO centrality dependence of RAAat √sNN = 22.4 GeV Norbert Novitzky for PHENIX

  7. dN/dh and dET/dhenergy scan There is no significant change in the centrality dependence of dN/dh and dET/dh distributions in energy range of 7.7 GeV Au+Au – 2.76 TeVPb+Pb. Norbert Novitzky for PHENIX

  8. Bjorken energy density = transverse overlap area of the nuclei. Determined from the Glauber model. t = formation time dET/dh is multiplied by 1.25 to obtain dET/dy at SPS energies. Norbert Novitzky for PHENIX

  9. v2 in energy scan Phys. Rev. Lett. 105, 142301 (2010) Is v2 saturated in √sNN=39-200GeV? From RHIC to LHC the increase is due to the increase of mean-pT arXiv:1011.3914 Norbert Novitzky for PHENIX

  10. p0 invariant yields of the Au+Au at 62.4 and 39 GeV 62.4 GeV • To lower √s the contribution from other processes are larger: • Running a(Q2) • PDF evolution • kTsmearing • Higher-twist phenomena The minimum bias spectra are fitted with a power-law shape function for pT > 4 GeV/c : 39 GeV In LO of the QCD: n200GeV = 8.06 ± 0.03 n62GeV = 10.60 ± 0.03 n39GeV = 13.1 ± 0.1 arXiv:1204.1526v1 Norbert Novitzky for PHENIX

  11. xTscaling – I. The xT scaling law for the hard scattering region: The n(xT) should equal to 4 in LO QCD. The isolated photons show the xT scaling with the n(xT)=4.5 The LO QCD is dominant process for the isolated photons ArXiv:1202.1762 Norbert Novitzky for PHENIX

  12. xTscaling – II. arXiv:1204.1526v1 Extracting the power with the linear variation of the logarithm of the ratio of the yields at different √sNN: • All p+p data shows similar scaling behavior and the neff(xT) are comparable • The 62.4 and 200 GeV Au+Au data agrees with the p+p data • The neff(xT) of the 39 and 200 GeV Au+Au show the xT scaling is not working below xT< 0.2 (the end of overlapping region) Norbert Novitzky for PHENIX

  13. 62.4 GeV p+p reference extrapolation • Data from PHENIX are available up to • pT < 7 GeV/c • To extrapolate to higher pT points power-law function was used: • The limit of the fits is vital • ––> systematic errors. • The systematic uncertainty is calculated from the errors of the power-law fit • It agrees well with the CCOR data (ISR) in pT 7-10 GeV/c region • For extrapolation the fit above pT>3.5 GeV is used Norbert Novitzky for PHENIX

  14. 39 GeV p+p reference • p+p data measured only in fix-target experiment by E0706 at Tevatron with 800 GeV beam energy. (Phys.Rev.D68:052001,2003) • The E0706 has different rapidity acceptance • -1.0 < y < 0.5 (PHENIX |y|<0.35). Acceptance correction function E0706  PHENIX • Acceptance correction based on PYTHIA8 simulation. • The systematic uncertainty of the correction function is calculated based on data to PYTHIA8 comparison. Norbert Novitzky for PHENIX

  15. RAA in energy scan arXiv:1204.1526v1 • RAA at 39 GeV shows strong suppression in the most central collision. • The 62.4 and 200 GeV RAA data points are comparable for pT > 6 GeV/c. • In mid-peripheral collision, 39 GeV data shows so suppression while in higher √sNNthe suppression is still significant. • The data in most central collision are compared with two calculation of the GLV model, where the difference is the magnitude of the Cronin effect. Norbert Novitzky for PHENIX

  16. RAAvs pTin all centralities arXiv:1204.1526v1 RAA towards more peripheral region shows less suppression. 62.4 and 200 GeV are similar for pT > 6 GeV Norbert Novitzky for PHENIX

  17. pT averaged arXiv:1204.1526v1 • RAA in different sNN: • 62.4-200 GeV are strongly suppressed • 39.0 GeV data shows suppression for higher centrality only (Npart>100) • For pT > 6 GeV/c the 62.4 and 200 GeV data points are comparable Norbert Novitzky for PHENIX

  18. Fractional Energy-Loss The definition of the energy loss is the “horizontal” shift of the p+p spectrum towards the TAA scaled Au+Au spectra: = 0 Fractional energy loss: TAA*(p+p) dpT/pT Au+Au (0-10%) Norbert Novitzky for PHENIX

  19. Sloss arXiv:1204.1526v1 • The fractional energy loss study: • 200 GeV exhibits the largest energy loss • 62 GeV and 39 GeV data points are in agreement for pT<5 GeV/c Norbert Novitzky for PHENIX

  20. Slossin all centralities arXiv:1204.1526v1 Same results as the RAA: Towards more peripheral collisions the energy loss is decreasing. In mid-peripheral collision the 39 GeV data have “negative” energy loss. Consistent with RAA>1. Norbert Novitzky for PHENIX

  21. Summary PHENIX after 10 years of data taking in the inclusive sector: • Centrality dependence of global observables do not change from 7.7 GeV to 2.76 TeV. • xTscaling: neff(xT) for 39 and 200 GeV is very different in p+p and Au+Au • p0 v2 seems to saturate already at 39 GeV - 200 GeV • p0 RAA was measured in lower energies: • The 39 GeV most central is still suppressed • 62.4 and 200 GeV are comparable for pT>6 GeV/c • 39 GeV shows suppression for Npart>100 Norbert Novitzky for PHENIX

  22. Backup Norbert Novitzky for PHENIX

  23. Theory vs Data Norbert Novitzky for PHENIX

  24. RAA in Bjorken energy density + ALICE data? Norbert Novitzky for PHENIX

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