Heavy Flavor Tagged Jet RHIC Anne Sickles May 20, 2009

2 Anne Sickles May 20, 2009 Heavy Ion Collision illustration: S. Bass incoming nuclei hot matter hadronic gas RHIC: ion-ion collisions at up to √s NN =200GeV also p+p collsions, crucial baseline

3 Anne Sickles May 20, 2009 Au+Au collision

4 Anne Sickles May 20, 2009 hot nuclear matter consistent with initial T ~ MeV arXiv: excess: 221±23±18MeV Direct γ central Au+Au: large excess over binary scaled p+p p+p central Au+Au arXiv:

5 Anne Sickles May 20, 2009 high p T particle production Parton Distribution Functions: Measured in Deep Inelastic Scattering Hard Scattering Cross Section: Calculated with pQCD Fragmentation into Hadrons: Measured in e+e- Collisions jet p+p collisions

6 Anne Sickles May 20, 2009 high p T particle production Parton Distribution Functions: Measured in Deep Inelastic Scattering Hard Scattering Cross Section: Calculated with pQCD Parton-Medium Interactions & Hadron Formation jet Au+Au collisions

7 Anne Sickles May 20, 2009 γ : control measurement R AA = 1 no nuclear effects γ: no color charge → insensitive to produced matter R AA (p T <14GeV/c) consistent with unity R AA = yield pp * N coll yield AA

8 Anne Sickles May 20, 2009 π 0 : light meson R AA = yield pp * N coll yield AA R AA << 1 parton energy loss

9 Anne Sickles May 20, 2009 Heavy Flavor via Semi-leptonic decays single particles: measure e ± from D, B decay hadronic decays: large backgrounds DecayBranching Ratio D ± →e+X16.0% D 0 →e+X6.5% problem: how do you know if e ± came from charm or bottom?

10 Anne Sickles May 20, and heavy quarks? electrons from decay of heavy mesons are modified by the matter in heavy ion collisions yields are suppressed at nearly same level as π 0 PHENIX, PRL (2007) heavy quarks are a good probe of hot nuclear matter!

11 Anne Sickles May 20, 2009 heavy quark energy loss radiative energy loss should be suppressed for heavy quarks: “dead cone effect” (Dokshitzer & Kharzeev) some calculations expect large collisional energy loss experimental question: how does the energy loss pattern of heavy quarks differ from light partons? R AA (charm)/R AA (light quarks)

12 Anne Sickles May 20, 2009 final state effects jets are produced before the matter, but the see the entire lifetime of the system final state effects could change which hadrons are formed jet PHENIX PRC (2006)

13 Anne Sickles May 20, 2009 recombination quark momenta add: p T (hadron) > p T (quark) baryons get an extra boost→extra quark if heavy quarks also recombine, it could lower their R AA heavy baryons don’t decay into electrons as much as mesons Fries et al., Hwa et al., Ko et al. basic idea: valence quarks coalesce to form final state hadrons

14 Anne Sickles May 20, 2009 D/B in medium formation D/B form & dissociate in the matter: τ form α p T τ formD (10GeV/c)=1.6fm/ c τ formB (10GeV/c)=0.4fm/ c expect to see extra hadrons on the near side from the D & B energy loss Adil & Vitev PLB (2007)

15 Quark Matter 2009 Anne M. Sickles March 31, particle correlations complementary to single particle observables different sensitivity to geometry sensitive to energy flow I AA = conditional yield in AuAu conditional yield in pp quantifcation

16 Anne Sickles May 20, 2009 Mach Cones? hadron correlations Mach Cones? PRL (2007) cone angle: change θ m by changing: →√sNN jet velocity →massive partons

17 Anne Sickles May 20, 2009 changing beam energy PHENIX, PRL (2007) Pb-Au 17.3 GeV 0-5% CERES Preliminary heavy quarks change the jet velocity!

The Landscape: Heavy Flavor in p+p

19 Anne Sickles May 20, 2009 charm & bottom: theory D→e B→e B→D→e bands show theoretical uncertainty (FONLL) in components Single electrons from heavy flavor R. Vogt, QM2005 knowledge of relative c/b contributions crucial for understanding HF modifications in Au+Au collisions

20 Anne Sickles May 20, 2009 what can experiment say? heavy meson decay: e & K have opposite signs like sign pairs approximate the background compare to simulations to get relative contributions from charm and bottom idea: D→eKν, reconstruct eK invariant mass arXiv: [nucl-ex]

21 Anne Sickles May 20, 2009 relative b→e contribution vs p T,e significant bottom contributions good agreement with FONLL arXiv: [nucl-ex]

22 Anne Sickles May 20, 2009 two types of electrons PHENIX, PRL (2006) Heavy FlavorPhotonic Electrons

23 Anne Sickles May 20, 2009 separating the correlations PHENIX, PRL (2006)

24 Anne Sickles May 20, 2009 e phot -h correlations photonic electrons: Dalitz decays and γ conversions dominantly from π 0 s measure γ inc -h correlations also dominantly from π 0 s use MC to map between e phot (p T ) & γ inc (p T )

25 Anne Sickles May 20, 2009 e phot -h correlations (II) γ inc (p T ) ➡ e phot (p T ) ? conversions: γinc(pT) + PHENIX GEANT + reco. eff. Dalitz decays: π 0 (p T ) → γe + e - get γ* from e + e - both methods: e phot (p T ) ~ γ inc (p T ) ≈ π 0 (p T ) π 0 spectrum falls very steeply γ p T (GeV/c) w 3.0<p T,e <3.5GeV/c

26 Anne Sickles May 20, 2009 e inc -h correlations

27 Anne Sickles May 20, 2009 adding e phot -h...

28 Anne Sickles May 20, 2009 heavy flavor correlations

29 Anne Sickles May 20, 2009 near side widths σ HF > σ phot : D/B decay kinematics good agreement with PYTHIA (charm production)

30 Anne Sickles May 20, 2009 charm production subprocesses Vitev et al PRD (2006) cg→cg cq(q)→cq(q) gg→cc qq→cc cc→cc most of the time a D is not balanced by a mid-rapidity D (caveat: LO calculation)

31 Anne Sickles May 20, 2009 Next to Leading Order POWHEG NLO Monte Carlo: 2→2 & 2→3 processes light parton jets are a significant contribution to the away side correlations

32 Anne Sickles May 20, 2009 Light Quark Fragmentation fragmentation functions from e + e - collisions most particles carry small fraction of jet energy Particle Data Book

33 Anne Sickles May 20, 2009 what about heavy quark jets? c→D fragmentation hard b→B fragmentation harder c→D fragmentation b→B fragmentation Particle Data Book

34 Anne Sickles May 20, and the rest of jet energy? de Florian et al PRD (2007) c,b → hadrons softer than q, g jets

35 Anne Sickles May 20, 2009 conditional yields near side: heavy quarks, dominated by decays away side: heavy & light partons, fragmentation and decays

36 Anne Sickles May 20, 2009 comparison to light jets PHENIX PRD (2006) π 0 -h, p+p e HF -h same p T,trig (≠p T,parton )

effects of the matter... Au+Au

38 Quark Matter 2009 Anne M. Sickles March 31, 2009 energy loss: π 0 -h v γ direct -h π 0 -h γ direct -h g,q interact strongly--energy loss γ don’t interact strongly no surface bias surface bias p T,π0 < p T,jet p T,γ ~ p T,jet away side more likely to be quark: q + g → q + γ

39 Quark Matter 2009 Anne M. Sickles March 31, 2009 π 0 -hadron: opacity π 0 : 5 < p T < 7GeV/c π 0 : 7 < p T < 9GeV/c π 0 : 9 < p T < 12GeV/c I AA suppression nearly constant with p T,trig p T,h

40 Anne Sickles May 20, 2009 I AA : π 0 -h & γ direct -h no significant difference between π 0 -h and γ dir -h suppression just how important is the π 0 surface bias?

41 Anne Sickles May 20, 2009 π 0 -h: away side shape increasing π 0 p T →more data! no evidence for double peaks for very high p T π 0 don’t have the statistical precision to exclude it

42 Anne Sickles May 20, 2009 π 0 -h: away side shape? I AA dominated by punch through jets

43 Quark Matter 2009 Anne M. Sickles March 31, 2009 Heavy Flavor: Au+Au

44 Quark Matter 2009 Anne M. Sickles March 31, 2009 Au+Au vs p+p

45 Quark Matter 2009 Anne M. Sickles March 31, 2009 heavy flavor: I AA large errors I AA (near side) ~ 1 consistent with D decays I AA (1.25-π) > I AA (2.51-π) evidence for shoulder? ΔΦ2.0<p Te <3.0GeV/c rad1.17± πrad1.43± πrad0.67±0.16

46 Quark Matter 2009 Anne M. Sickles March 31, 2009 conclusions open heavy flavor is an important frontier in jet physics complementary to γ-h & π 0 -h measurements it will be crucial for energy loss & hadronization models to describe all these observables however, it is harder to interpret, more statistics starved and a harder measurement than γ-h or π 0 -h

47 Quark Matter 2009 Anne M. Sickles March 31, 2009 a promising future p+p: jet properties & understanding parton subprocesses Run 10: 200 GeV Au+Au: 4-6x statistics for PHENIX e HF -h luminosity & acceptance increases Hadron Blind Detector can reject some photonic electrons further improving the measurement 2-3x statistics for π 0 -h & γ dir -h Run 11: Silicon Vertex Detector: separation of charm and bottom

48 Quark Matter 2009 Anne M. Sickles March 31, 2009 ΔΦ1.5<p Te <2.0GeV/c2.0<p Te <3.0GeV/c3.0<p Te <4.0GeV/c rad0.53± ± ± πrad1.18± ± ± πrad0.52± ± ±0.31 I AA straight line fits

49 Anne Sickles May 20, 2009 conclusions & outlook c/b ratio in p+p consistent with FONLL this ratio crucial to understanding e± results in Au+Au e HF -h conditional yields in p+p measured method established to extract HF correlations useful for testing charm fragmentation into hadrons baseline for Au+Au results, being analyzed now HF correlations provide a new tool to study passage of fast parton through matter

50 Anne Sickles May 20, 2009 Double Peak Structure PHENIX, PRC (2008), Noronha et al. arXiv: , Neufeld arXiv: AdS/CFT: Correlations from Neck region Hydro: Mach Cone width & strength sensitive to η/s Heavy quark correlations should help discriminate!

51 Anne Sickles May 20, 2009 RAA of hadrons p T (GeV/c) STAR preliminary

52 Anne Sickles May 20, 2009 and what about heavy quarks? 1.04 for a 4 GeV bottom quark 1.2 for a 3GeV charm quark work backward, if you wanted to see this number march in to 0.7 at RHIC you would need v= 0.45 which is a 2.3GeV bottom quark

53 Anne Sickles May 20, 2009 are the measurements sensitive? phasecScS θ M (rad) QGP1/√3 ~ hadron gas√0.2 ~ mixed phase01.57? RHIC (time average) numbers from: Casalderry-Solona, et al hep-ph/