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Kwangbok Lee Korea University

Heavy Ion physics and heavy quarkonia : focused on Upsilon and chi_c measurement. Kwangbok Lee Korea University. Outline. Heavy Ion physics - A + A collision -> J/psi, heavy quarkonia - p ( d ) + A collision (Cold nuclear matter)

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Kwangbok Lee Korea University

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  1. Heavy Ion physics and heavy quarkonia: focused on Upsilon and chi_c measurement Kwangbok Lee Korea University Kwangbok Lee - 22 Nov. 2010

  2. Outline • Heavy Ion physics - A + A collision -> J/psi, heavy quarkonia - p(d) + A collision (Cold nuclear matter) -> Shadowing effect, nuclear absorption, gluon saturation, initial state energy loss • Υmeasurement in d + Au collision (Preliminary) • ccmeasurement in d + Au collision (Challenging, ongoing) • Future prospect Kwangbok Lee - 22 Nov. 2010

  3. Heavy Ion physics present First Supervovae Galaxy & Star Formation Atom Formation He Formation WI & QED Separate Quark Gluon Plasma EW & QCD Separate (GUT) Big Bang The phase diagram of QCD matter History of the Universe Kwangbok Lee - 22 Nov. 2010

  4. Heavy Ion Collision 1. About to collide 4. Hadronize(Freeze out) 2. Collide 3. QGP Time Time The space-time diagram of a heavy ion collision Kwangbok Lee - 22 Nov. 2010

  5. SPS RHIC Energy Density J/psi suppression • Several scenarios may contribute: • Suppression by the color screening • Cold nuclear matter (CNM) effect • Regeneration effect Satz, hep-ph/0512217 Sequential J/ψ suppression by colour screening Charmonium system Kwangbok Lee - 22 Nov. 2010

  6. Quarkonia & Color deconfinement cc bb • Each quarkonium has different • binding radius. hep-ph/0609197v1 H. Satz hep-ph/0512217 Schematic of color screening • At RHIC, Υ3Smelts and the Υ2S is likely to melt, the Υ1S • is expected to survive. - S. Digal et.al., Phys. Lett. B 514 (2001) 57. • C-Y Wong, Phys. Rev. C 72 (2005) 034906. Kwangbok Lee - 22 Nov. 2010

  7. Cold Nuclear Matter (CNM) • Since, in p(d)A collisions, no hot and dense medium is expected to be created, • the matter created is called cold nuclear matter (CNM). • The CNM can provide the quantitative comparison to the measurement of A + A collision • so can provide a better understanding of the effects beyond CNM from hot and dense • nuclear matter. • CNM is an interesting matter itself. B B A B A B A A Schematic illustration of Au + Au collision Schematic illustration of d + Au collision Kwangbok Lee - 22 Nov. 2010

  8. low x high x Cold Nuclear Matter (CNM) Q2 = 1.69 GeV2 nDS • Shadowing model • Nuclear absorption • Initial state parton energy loss antishadowing HKN07 EKS98 EPS09 EPS08 shadowing X2 J/y Υ1S RGPb Υ1S J/y arXiv:0902.4154 Gluon density in different x Rapidity Kwangbok Lee - 22 Nov. 2010

  9. Nuclear modification factors Ncoll: number of binary (pp) collisions in one HI collision. • If the production of AA behaves like in pp, • RdAu = Rcp= 1 • If there is suppression, RdAu , Rcp< 1 Kwangbok Lee - 22 Nov. 2010

  10. Upsilon analysis • Run 8 (2008) d+Au data and Run 6 (2006) p+p data are used. • -> provide Upsilon cross section, σΥ and Upsilon nuclear modification factor, RdAu. • Physical backgrounds of Drell Yan, open charm and open beauty • are simulated and excluded. • (Recently, we got NLO Drell Yan calculation, so doing updates). Kwangbok Lee - 22 Nov. 2010

  11. PHENIX Muon arm Au d + - South North <y> ~ -1.7, x2 ~ 0.2 Gold going direction <y> ~ 1.7, x2 ~ 0.01 deuteron going direction thought to be in shadowing region Kwangbok Lee - 22 Nov. 2010

  12. Invariant mass distribution • Unlikesign event • Scaled Mixed event • Signal : Unlikesign – • Scaled Mixed event • Estimated combinatorial background by event mixing • There might be physical background in Upsilon mass region such as Drell-Yan, correlated open beauty and correlated open charm Kwangbok Lee - 22 Nov. 2010

  13. Drell-Yan process - simulation • DY events were embedded to real data to reflect more realistic environment. • Fit the reconstructed points with exponential function. • Shape and absolute value are extracted to fit the real data. Kwangbok Lee - 22 Nov. 2010

  14. Correlated open beauty - simulation • Pythia generation and generation by randomizing ϕ angle were considered. • Reconstructed through PHENIX simulation application chain. Kwangbok Lee - 22 Nov. 2010

  15. Correlated open charm - simulation • Did same procedure with correlated beauty estimation. • Charm isn’t estimated to affect Upsilon mass range much. Kwangbok Lee - 22 Nov. 2010

  16. Upsilon - simulation Kwangbok Lee - 22 Nov. 2010

  17. Fitting real data (p + p data set) • Drell Yan, correlated bottom, correlated charm and Upsilon • are considered to fit the data points. • Apply the shape and the absolute value of each component from simulation to • fit the data. Kwangbok Lee - 22 Nov. 2010

  18. Fitting real data (d + Au data set) • Drell Yan, correlated bottom, correlated charm and Upsilon • are considered to fit the data points. • Apply the shape and the absolute value of each component from simulation to • fit the data. Kwangbok Lee - 22 Nov. 2010

  19. Upsilon cross section in p + p • Shape matches CEM well (scaled down by factor of 2) BR*dσ/dy = 28.2±9.4(stat.)±4.8(syst.)pb, y [-2.2, -1.2] BR*dσ/dy = 31.1±8.7(stat.)±6.2(syst.)pb, y [1.2, 2.2] Kwangbok Lee - 22 Nov. 2010 19

  20. Upsilon RdAu in d+Au/p+p • Shows suppression at low x region RdAu = 0.84±0.34(stat.)±0.20(sys.), y [-2.2, -1.2] RdAu= 0.53±0.20(stat.)±0.16(sys.), y [1.2, 2.2] Kwangbok Lee - 22 Nov. 2010

  21. Another Upsilon measurements RdAu = 0.78+-0.28(stat.) +-0.20(sys.) at mid rapidity RAuAu < 0.64 at 90% C.L. at mid rapidity Kwangbok Lee - 22 Nov. 2010

  22. chi_c Analysis • Run8 d+Au collision and Run8 p+p collision are being analyzed. • Small MPC acceptance -> big uncertainties -> make the analysis hard. • Let me show the status. Kwangbok Lee - 22 Nov. 2010

  23. chi_c Analysis • Higher charmonium state(1P) than J/ψ(1S). • There are three states of chi_c. • Radiative decay channelcc -> J/ψ +γ-> μ+μ-(e+e-) + γ. • Rcc= (cc -> J/ψ +γ ) / (Inclusive J/ψ). • It would be a good tool to decouple the fraction of decay J/ψ and direct J/ψ. PDG 10’ Kwangbok Lee - 22 Nov. 2010

  24. How can we detect chi_c? γ d Au + Forward E.M. Calorimeter (MPC) 3.1 < |y| < 3.9 - South North MPC Muon arm Kwangbok Lee - 22 Nov. 2010

  25. MPC MPC PHENIX acceptance Backward & Forward Calorimetry South Muon Tracker North Muon Tracker EMCAL + Central Tracker 0 f coverage 2p EMCAL + Central Tracker -3 -2 -1 0 1 2 3 rapidity Kwangbok Lee - 22 Nov. 2010

  26. MPC acceptance by Pythia Kwangbok Lee - 22 Nov. 2010

  27. MPC photon energy distribution Low energy background !! Inclusive photon energy in MPC Chi_cdecay photon energy in MPC Kwangbok Lee - 22 Nov. 2010

  28. Kinematic cuts (2D) Single cc photon vs J/ψ rapidity Embedded cc photon vs J/ψ rapidity Kwangbok Lee - 22 Nov. 2010

  29. chi_c1 embedding simulation Foreground event Scaled mixed event Signal(Foreground – Mixed) Peak : 0.429 GeV Peak : 0.424 GeV North arm South Arm x-axis: μ+μ-γ(three particle correlated mass) – μ+μ-(dimuon mass) Kwangbok Lee - 22 Nov. 2010

  30. Fitting to real data (p + p data set) Foreground event Scaled mixed event Signal(Foreground – Mixed) Signal fitting with 2 Gaussians South Arm North arm Kwangbok Lee - 22 Nov. 2010

  31. Fitting to real data (d + Au data set) Foreground event Scaled mixed event Signal(Foreground – Mixed) • Peak is visible at small x region. • South MPC has large background. • Rccvaries from 0.8 ~ 1.5 depending the cc • distributions. • Rccvalues are still lager than expected. • Trying to figure out where the enhancement • comes from. dAu North Kwangbok Lee - 22 Nov. 2010

  32. Another chi_c measurement World average is about 0.3. But it has large fluctuations and uncertainties. Kwangbok Lee - 22 Nov. 2010

  33. prompt pm PHENIX upgrade • Silicon VTX, Silicon FVTX(LANL), • Muon trigger/RPC, etc. • Silicon Forward Vertex (FVTX). • -> Displaced vertex, Mass resolution. • First Drell-Yan from RHIC. • Separation of charm and beauty. Kwangbok Lee - 22 Nov. 2010

  34. Summary • Quarkonia measurement is a good probe to understand matter created in the heavy ion collision. • New Upsilon RdAu shows suppression in low x region and need to have theoretical comparison. • ccfeed down to J/y measurement is underway and will be important to decouple the cold nuclear matter effect and QGP state. Kwangbok Lee - 22 Nov. 2010

  35. Future • PHENIX detector upgrade is ongoing recently.. - Silicon VTX, Silicon FVTX(LANL), Muon trigger/RPC, etc. • Forward Silicon Vertex Detector (FVTX), led by the LANL group, will measure displaced vertices of the produced particles and improve the mass resolutions. • With the FVTX, we expect to separate the Drell-Yan process, open charm and openbeauty. Kwangbok Lee - 22 Nov. 2010

  36. Back up

  37. NLO Drell Yan estimation Kwangbok Lee - 22 Nov. 2010

  38. PHENIX Muon Piston Calorimeter Technology  ALICE(PHOS) PbWO4 avalanche photo diode readout Acceptance: 3.1 < η < 3.9, 0 < φ < 2π -3.7 < η < -3.1, 0 < φ < 2π Both detectors were installed for 2008 d-Au run. Assembly at UIUC PbWO4 + APD + Preamp MPC integrated in the piston of the muon spectrometer magnet. 38 Kwangbok Lee - 22 Nov. 2010 38

  39. Chi_c distribution andRcc σ = 1.5 Give different MPC acceptance of 3.8 % ~ 5.7 % ccrapidity Decay γ rapidity σ=flat • Rccvaries from 0.8 ~ 1.5 by the cc distributions. • Rccvalues are still lager than expected. • Trying to figure out where the enhancement comes from. Kwangbok Lee - 22 Nov. 2010

  40. Uncertainty summary Table. Uncertainty summary Kwangbok Lee - 22 Nov. 2010

  41. Invariant yield and cross sections Kwangbok Lee - 22 Nov. 2010

  42. Fit conditions Table. Summary of fit conditions Red: nominal setting, Blue: setting for systematic error estimation, Green: free parameter Kwangbok Lee - 22 Nov. 2010

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