1. Cold Nuclear Matter Effects on Open Heavy Flavor at RHIC J. Matthew Durham for the PHENIX Collaboration Stony Brook University durham@skipper.physics.sunysb.edu

2. Matt Durham - WWND 2011 2 Open Heavy Flavor at RHIC Phys. Rev. Lett. 98, 172301 (2007) One of the most striking results from RHIC is the strong suppression and flow of heavy quarks in Au+Au collisions d+Au Au+Au d+Au allows quantification of nuclear effects without complications of hot medium

3. Matt Durham - WWND 2011 3 Cold Nuclear Matter Effects Phys. Rev. C 74, 024904 (2006) Mass ordering of Cronin enhancement observed for π,K,p Does this continue with D meson? B? M D ~1.8 GeV Closed heavy flavor is suppressed at mid-rapidity (details in Alex’s talk next) Open heavy flavor in d+Au can shed light on these interesting phenomena arXiv:1010.1246

4. Matt Durham - WWND 2011 4 Measurement Methodology Direct Reconstruction: Identify parent meson via daughter products Indirect Method: Measure leptons from D/B decays Straightforward triggering scheme PHENIX is especially well suited for lepton measurements

5. Matt Durham - WWND 2011 5 2007-12-14 The PHENIX Experiment  Electrons are tracked by drift chamber and pad chamber  The Ring Imaging Cherenkov Counter is primary electron ID device  Electromagnetic calorimeters measure electron energy – allow E/p comparisons  BBC/ZDC provide MinBias trigger and centrality determination in HI collisions e+e+ ee   Run-8 Configuration

6. Matt Durham - WWND 2011 6 Electron Sources Dalitz decays Mostly Also from Conversions in material Photons predominantly from Kaon decays Dielectron decays of vector mesons Thermal/direct radiation Small but significant at high pt Heavy Flavor Decays SIGNAL BACKGROUND

7. Matt Durham - WWND 2011 7 Background Subtraction Methods Cocktail Method PHENIX has measurements of most of the background electron sources. A cocktail of these sources are subtracted from the inclusive electron sample to isolate the HF contribution. Converter Method Extra material in the PHENIX aperture intentionally increases background by a well defined amount. Allows precise quantification of photonic background. arXiv:1005.3674

8. Matt Durham - WWND 2011 8 Conversions  Vast majority of conversion electrons come from photons from, with kinematics very similar to  Scale up Dalitz decay electrons by appropriate factor to account for conversions (determined through simulation) Cocktail Ingredients I Light mesons  Fit d+Au pion data with Hagedorn function  Set other meson’s shape with mt-scaling  Normalization set by particle ratios at high pt

9. Matt Durham - WWND 2011 9 Cocktail Ingredients II Direct Photons  PHENIX p+p data, scaled up by N coll for each centrality K e3 decays  Electrons from kaon decays away from the vertex are mis- reconstructed at high p T.  Full simulation of PHENIX detector determines K e3 contribution (only relevant at p T <1GeV/c) A note on the J/ψ:  We know J/ ψ is suppressed in d+Au  We don’t yet have kinematic dependence of J/ ψ R dA  J/ ψ is significant at high p T, so knowledge of the exact behavior at p T >4GeV/c is necessary to correctly account for this contribution  As of now, J/ ψ is not subtracted

10. Matt Durham - WWND 2011 10 Total MB Cocktail

11. Matt Durham - WWND 2011 11 Converter Method For one day in Run-8, a brass sheet was wrapped around the beam pipe. This increases photonic background by a well defined amount. Precise measurements of converter material allow precise determination of R γ via simulation

12. Matt Durham - WWND 2011 12 Cocktail and Converter Comparison Cocktail method gives a calculation of photonic background Converter method gives us a measurement of photonic background Difference is ~10% for all centralities. Photonic cocktail components scaled to match converter data.

13. Matt Durham - WWND 2011 13 Photonic Backgrounds Excellent agreement between the two methods

14. Matt Durham - WWND 2011 14 Heavy Flavor Electron Spectra Subtract cocktail from the inclusive electron sample to obtain the HF contribution Black line is N coll scaled fit to p+p With d+Au spectra, divide by scaled p+p reference to obtain R dA

15. Matt Durham - WWND 2011 15 Peripheral R dA

16. Matt Durham - WWND 2011 16 Semi-Peripheral R dA

17. Matt Durham - WWND 2011 17 Semi-Central R dA

18. Matt Durham - WWND 2011 18 Central R dA

19. Matt Durham - WWND 2011 19 Minimum Bias R dA

20. Matt Durham - WWND 2011 20 Peripheral R dA consistent with p+p Enhancement in open HF yields at 1<p T <4 GeV/c for more central collisions Suppression at the highest p T R cp allows examination of “turn- on” of these effects within d+Au (with much smaller systematics) A few comments on R dA

21. Matt Durham - WWND 2011 21 R cp (40-60)/(60-88)

22. Matt Durham - WWND 2011 22 R cp (20-40)/(60-88)

23. Matt Durham - WWND 2011 23 R cp (0-20)/(60-88)

24. Matt Durham - WWND 2011 24 Light QuarksHeavy Quarks Phys. Rev. Lett. 101, 232301 (2008) arXiv:1005.1627 Phys. Rev. Lett. 98, 172302 (2007)

25. Matt Durham - WWND 2011 25 At pT> 4 GeV/c: At pT< 4 GeV/c:

26. Matt Durham - WWND 2011 26 Summary PHENIX now has a full suite of heavy flavor measurements across a wide range of N coll and colliding systems. The Run-8 d+Au data set shows:  Enhancement of open HF at moderate pT  Suppression at the highest pT This new reference for A+A data suggests heavy quark energy loss in the medium is even greater than previously thought:  Is the apparent difference in energy loss for light and heavy quarks really just a CNM effect?

27. Matt Durham - WWND 2011 27 BACKUPS

28. Matt Durham - WWND 2011 28 A. Dion, QM09

29. Matt Durham - WWND 2011 29 Centrality Determination in d+Au

30. Matt Durham - WWND 2011 30

31. Matt Durham - WWND 2011 31 Heavy Flavor Electron Spectra

32. Matt Durham - WWND 2011 32 Heavy Flavor Electron Spectra

33. Matt Durham - WWND 2011 33 Heavy Flavor Electron Spectra

34. Matt Durham - WWND 2011 34 Heavy Flavor Electron Spectra