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Open Charm and Charmonium Production at Large Rapidity in d+Au Collisions at RHIC

Open Charm and Charmonium Production at Large Rapidity in d+Au Collisions at RHIC. Ming X. Liu Los Alamos National Lab (for the PHENIX Collaboration). The PHENIX Detectors. gold. deuteron. North Muon arm : 2.4 > h > 1.2. South Muon arm : -1.2 > h > -2.0. High pT light hadrons. ♦. ♦.

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Open Charm and Charmonium Production at Large Rapidity in d+Au Collisions at RHIC

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  1. Open Charm and Charmonium Production at Large Rapidity in d+Au Collisions at RHIC Ming X. Liu Los Alamos National Lab (for the PHENIX Collaboration) M. Liu DNP05

  2. The PHENIX Detectors gold deuteron North Muon arm : 2.4 > h > 1.2 South Muon arm : -1.2 > h > -2.0 M. Liu DNP05

  3. High pT light hadrons ♦ ♦ ♦ ♦ ♦ Brahms (h++h-)/2 ( =0, 1.0, 2.2) pT =1.75 Physics Questions • Cold nuclear medium effects: • Parton distributions • gluon (anti)shadowing • CGC • Interactions with medium • Parton energy loss • QCD Power Correction • Recombination • New probes: • Charm M. Liu DNP05

  4. yield y X Gluon Shadowing in Heavy Nucleus From Eskola, Kolhinen, Vogt Nucl. Phys. A696 (2001) 729-746. Universal M. Liu DNP05

  5. Shadowing: Color Glass or Dynamic Multiple Scattering Power Correction? J. Qiu & I. Vitev Power correction only • A challenge! • Explore (x, Q) space • pT (Q^2) evolution • Collision energy scan • Different probes: light vs heavy! D. Kharzeev & K. Tuchin hep-ph/0310358 CCG M. Liu DNP05

  6. Recombination • “Explains” light hadron yields in forward and backward rapidities • Input: low pT forward /backward hadron distributions • Expect similar effects on open charm(?) • Charm + light quarks • Hard fragmentation-> minimal effects? • No detailed calculation yet(?) • Measurement of charm yields could provide additional constrains on these models H M. Liu DNP05

  7. Decay muons Punch-through hadrons ? Prompt muons m p,K absorber Muons from light and heavy meson decays The normalized muon event vertex distribution Muon detector Open heavy flavor production can be measured through prompt muons M. Liu DNP05

  8. RdAu from Open Charm or: • Initial parton energy loss • recombination X M. Liu DNP05

  9. 1.2 1.0 RdA 0.8 0.6 0.4 0.2 0 X How about J/Psi? • _NO_ Recombination! • Gluon shadowing/saturation • Initial state parton energy loss • J/Psi final state nuclear absorption has minimal effects on the shape M. Liu DNP05

  10. Shadowing or Energy Loss ? • Shadowing is not enough • Initial state energy loss? • Incoming gluons loss energy before the hard collisions • Affects low pT particle production in the FWD and BWD papidities M. Liu DNP05

  11. pT broadening: Cronin Effect Broadening of J/y pT distribution suggests initial scattering (maybe also energy loss) is important M. Liu DNP05

  12. Summary and Outlook • Physics at Forward and Backward Rapidity: • open charm • J/psi • Observed: heavy ~ ligh hadrons • suppression in the forward • enhancement in the backward • Causes for such effects are not very clear • Shadowing: CGC, Power correction • Initial state energy loss • recombination • Need more theoretical work • Need/Like to have: • Lower energy dAu collisions: stay away from shadowing regions • Explore { x, Q, sqrt(s) } space -> (y, pT, sqrt(s)) experimentally • Parton energy loss vs shadowing • pT evolution – shadowing vs power correction • Shadowing vs recombination • Explore QCD dynamics in details in coming years! M. Liu DNP05

  13. 1.2 1.0 0.8 RdA 0.6 0.4 0.2 0 backup M. Liu DNP05

  14. Probed X ranges in Au Prompt Muon Yields • Forward and backward bwd forward M. Liu DNP05

  15. Sources of prompt muons (pT> 0.9GeV) (determined from Pythia) D±±, … , c++, charge asymmetric B±  ± ±  ± *  + - charge symmetric q q  *  + - J/,… + - , ,  + - M. Liu DNP05

  16. Prompt muon and D correlation • Hard fragmentation • large <Z> • Strong correlations pT η(D) pT (muons) η (muon) M. Liu DNP05

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