1. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 1 Measuring open heavy flavor with the experiment Irakli Garishvili University of Tennessee for the PHENIX collaboration 25 th Winter Workshop on Nuclear Dynamics 09

2. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 2 Heavy quarks and QGP Created at the early stages of the heavy ion collision, heavy quarks are considered as extremely important probes of the created medium. In 90’s theorists were skeptical about importance of open heavy flavor for studying QGP medium. After early RHIC results heavy flavor was revisited. Initial theoretical models predicted much less in-medium effects compared to light quarks. Most recent results showed that for charm quarks and maybe for bottom quarks in-medium effects are comparable to those of light quarks.

3. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 3 D0D0 _ _ ν ℓ-ℓ- K+K+ D0D0 K-K- π+π+ Hadronic decay Semi-leptonic decay Semi-leptonic decay Tagging charm and bottom quarks c c - Non-photonic leptons: single electron measurement single muon measurement electron pair correlation e-μ correlation Hadron measurements: Direct measurement Enables e – h correlation

4. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 4 Identifying electrons with central arms Central arms: |η| 0.2 GeV/c excellent invariant mass measurement E/p for 1.0 < p T < 1.5 GeV/c 10 -6 MC (π 0 +K e3 ) Data Distributions absolutely normalized E/p Inside Cut Clean electron identification: RICH cut E/p cut in EMCAL Negligible hadron contamination

5. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 5 Measuring non-photonic electrons non-photonic electrons (c, b quarks) Inclusive electron spectra Background electrons = − γ p p e+ e- Converter Converter method Added converter material of known thickness (1.68% X 0 ) around beam pipe Increased photonic background by a well determined factor Cocktail method Measured background sources are used as the input for the “hadronic cocktail” Decay kinematics and photon conversions reconstructed by detector simulation.

6. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 6 Comparing cocktail and converter methods Good S/B > 1 for P T above 2GeV/c Converter method is used to renormalize cocktail. Good agreement between two methods. Extensive P T coverage S/B is essential input for v 2 analysis Signal/Background CONVERTER/COCKTAIL

7. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 7 Non-photonic electron spectra @ p+p 200GeV Necessary baseline measurement for heavy Ion collision Non-photonic electron spectra is consistent with FONLL (c+b) prediction Good agreement in spectral shape FONLL – Fixed Order Next to Leading Log M. Cacciari et al PRL 95, 122001 (2005) σ cc = 567 ± 57(stat) ± 224(sys) mb

8. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 8 Separating charm and bottom in p+p Used e – K correlation analysis. c/b ratio is necessary for measu- ring bottom cross-section Agreement with FONLL prediction Bottom becomes dominant above P T of 4GeV/c Bottom quark cross-section:

9. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 9 Independent cross-check: di-electron continuum measured correlated e - e + pairs Independent cross-check for calculation charm and bottom quark cross-sections: σ cc = 544 ± 39(stat) ± 142(sys) ± 200(model) mb σ bb = 3.9 ± 2.5(stat) ± 3 2 (sys) Good agreement with non- photonic electron results. arXiv:0802.0050 Predominantly c Predominantly b

10. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 10 R AA = 1 → boring R AA < 1 → suppression R AA > 1 → enhancement Non-photonic electron spectra @ Au+Au 200GeV Nuclear modification factor: PHENIX PRL98 173301 (2007) p+p spectra compared to 1.73*FONLL reference MinBias heavy quarks produced in point-like hard processes. production expected to scale with Total error from p+p

11. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 11 Nuclear modification factor Need to take into account other important in-mediums effects: - elastic collisions - coalescence with light quarks - collisional dissociation of heavy mesons - baryon enhancement Non-photonic e ± Very large suppression for non- photonic electrons, almost as much as for π 0 and η ! Initial theoretical models based solely on radiative energy loss doesn’t reproduce large suppression (dead cone effect). PHENIX PRL98 173301 (2007)

12. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 12 Elliptic flow/V 2 in heavy ion collisions improved v 2 measurement at high P T due to improved reaction plane resolution Run-7 (new reaction plane detector) Measurements in different centralities Spatial azimuthal anisotropy Non-photonic electron v 2

13. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 13 Do heavy quarks flow ? Agreement within errors between two datasets V 2 ≠ 0 for non-photonic electrons doesn’t necessarily mean that (V 2 ) HQ ≠ 0 Agreement with heavy quark transport Langevin model that includes elastic resonant scattering. PRELIMINARY Run-4 Run-7 Rapp & van Hees, PRC 71, 034907 (2005) minimum-bias Answer (for c quark): YES ! Answer (for b quark): Maybe Important to extend P T spectra and measure c/b ratio. 10 min. to lunch break

14. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 14 Forward rapidity Very important for understanding the full picture. Elliptic flow and nuclear modification factor has not been measured so far ! Single muon measurement should provide an important cross-check for non-photonic electron measurements. PHENIX J/ Ψ data indicates larger suppression in the forward rapidity! So open heavy flavor measurement may provide some valuable baseline information. J/ψ

15. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 15 Measuring heavy flavor with the muon arms SIGNAL: “Prompt” muons “Prompt” muons – muons resulting from decays of heavy quarksBACKGROUND: Decay muons Decay muons – muons from hadron decays Punchthrough hadrons Punchthrough hadrons – hadrons punching through the entire detector OTHER SOURCES Stopped hadrons Stopped hadrons – hadrons stopping in the shallow gaps due to nuclear interaction with the absorber. Gap 0 1 2 3 4 MuID Gaps 0 1 2 3 4

16. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 16 Estimating background with “Hadron Cocktail” - Cocktail is pre-constrained by matching with data - Generation of a “realistic” input P T spectra and mixture of dominant background sources (π, K, p …). - Particle propagation through PHENIX geometry using GEANT. - “Embedding” simulated tracks into real events to reproduce effects of detector environment during heavy ion collisions.

17. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 17 Adjusting/tuning cocktail to match data For muon/hadron separation, applying momentum cut on tracks that stop in gaps 2 & 3, keeping hadrons. We adjusted cocktail input by forcing simulated stopped hadron P T spectra to match data at gap 3. Finally, using additional data handles to check MC/data matching: 1) gap2 hadron spectra 2) Z vertex slope matching hadrons Normalized Z vertex

18. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 18 Non-photonic muon spectra @ p+p 200GeV Independent south/north arms cross-check Agreement with previous single muon result Large systematic errors in low P T region. Agreement at high P T with FONLL(c+b) prediction at y=1.65

19. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 19 Total charm cross-section in p+p: rapidity evolution Agreement with charm cross-section extracted from non-photonic electron.

20. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 20 Heavy flavor muon measurement in Cu+Cu @ 200GeV Run 5 MinBias triggered data. Rapidity range: 1.4 < |η|< 1.9 Different centrality classes: 0 – 20 % 20 – 40 % 40 – 94 % Will be the first single muon measurement in heavy ion collision environment in forward rapidity in intermediate P T range. Have already completed “hadronic cocktail” production. Close to results.

21. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 21 Summary Recent open heavy flavor measurements revealed larger suppression and elliptic flow than was originally expected. PHENIX has a wide range open heavy flavor measurements In heavy ion collisions: Au + Au: Non-photonic electron and di-electron spectra Cu + Cu: Single muon analysis (close to results) p+p collisions: - Single electron/muon measurements - di-electron spectra -charm/bottom separation OUTLOOK: Installing SVTX detector will improve vertex resolution, dramatically decreasing background in muon arms.

22. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 22 Back Up

23. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 23

24. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 24 J. – P. Blaizot, Theoretical summary, QM 99

25. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 25 decay component (~85%)  kinematics N tag = N unlike - N like D 0  e + K - (NO PID) reconstruction From data From simulation (PYTHIA and EvtGen) Main uncertainty of  c and  b  production ratios (D + /D 0, D s /D 0 etc) c,b separation in non-photonic electron background subtraction  (unlike-like) photonic component jet component tagging efficiency  when trigger electron is detected, conditional probability of associate hadron detectionin PHENIX acc  { jet component (~15%)

26. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 26 count tagging efficiency (  c,  b,  data ) reconstruction signal and simulation  2 /ndf 21.2/22 @b/(b+c)=0.26(obtained value) (0.5~5.0GeV)  2 /ndf 28.5/22 @b/(b+c)=0.42(obtained value) (0.5~5.0GeV)  2 /ndf 18.7/22 @b/(b+c)=0.56(obtained value) (0.5~5.0GeV) tag efficiency of charm increases as electron pt tag efficiency of data gets near bottom cc bb  data

27. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 27 10 min. to lunch break

28. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 28 Total error from p+p

29. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 29 Probing matter with heavy quarks Due to “heaviness”, c,b quarks created at early stages of heavy ion collisions, could carry important information on some properties of the created medium: – Thermalization – Jet quenching/Energy loss – Coalesence Key observables in A+A collisions: - Nuclear modification factor: - Elliptic flow/spatial azimuthal anisotropy: Measuring heavy quark production in p+p collisions: − baseline measurement for R AA calculation − pQCD cross-check

30. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 30

31. I. Garishvili, Univ. of Tennessee, - WWND 09, Big Sky, MT 31 Au+Au data