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WWND 03/13/06 N Grau1 Jet Correlations from PHENIX Focus entirely on A+A collisions High-trigger p T correlations –Can we do jet tomography? Low-trigger.

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Presentation on theme: "WWND 03/13/06 N Grau1 Jet Correlations from PHENIX Focus entirely on A+A collisions High-trigger p T correlations –Can we do jet tomography? Low-trigger."— Presentation transcript:

1 WWND 03/13/06 N Grau1 Jet Correlations from PHENIX Focus entirely on A+A collisions High-trigger p T correlations –Can we do jet tomography? Low-trigger p T correlations –Away-side shape modification –RP dependence An outlook –Direct  -h correlations, non-photonic e-h correlations Nathan Grau, Columbia University, Nevis Labs For the PHENIX Collaboration

2 WWND 03/13/06 N Grau2 Constructing Jet Correlations  Mixed events – corrects pair acceptance Hard scatteringResonance decays  (rad) Elliptic flowTotal C(  ) Sum over all events  jets measured on a statistical basis

3 WWND 03/13/06 N Grau3 Jet Quenching Single particle suppression pattern persists to 20 GeV Moderate p T jets are suppressed Due to energy loss of partons in the medium Pedestal&flow subtracted

4 WWND 03/13/06 N Grau4 Away-Side Jet in Au+Au! C(  ) strength ~ S/B of jets Red and blue lines are the uncertainty in v 2. Jets seen above the background for trigger >5 GeV/c and associated >2 GeV/c

5 WWND 03/13/06 N Grau5 Clear Away Side in Cu+Cu! Larger jet S/B in central Cu+Cu than central Au+Au v 2 modulation is smaller as well

6 WWND 03/13/06 N Grau6 Lack of Away-Side Broadening 8 < p T (trig) < 15 GeV/c Widths do not change between p+p and Au+Au?!? Trigger 5-10 GeV/c

7 WWND 03/13/06 N Grau7 Expected Broadening of Away Side Able to fit I AA from STAR. Red – gluons from energy loss. Black – scattering of parent partons I. Vitev hep-ph/0501255

8 WWND 03/13/06 N Grau8 Away Side Yield Suppression Away-side yield is suppressed?!? What mechanism can suppress yields without broadening them? –Tangential jets? –Punch through? 8 < p T (trig) < 15 GeV/c D. Magestro QM2005

9 WWND 03/13/06 N Grau9 Punch-through Events (I) Monte Carlo includes radial expansion reducing the effect of  E ~ L 2 Non-zero probability to lose no energy Does the away side carry away any information from the interior of the collision zone? Production vertices of events with trigger > 8 GeV Red circles indicate an associated hadron (> 4 GeV) suffering no E-loss T. Renk hep-ph/0602045

10 WWND 03/13/06 N Grau10 Punch-through Events (II) Yield suppression sensitive to the probability of punch-through Lower p T pairs are apparently more sensitive to energy loss… Comparison of MC to STAR away-side yields.

11 WWND 03/13/06 N Grau11 Lower p T Correlations h-h Correlations in Au+Au (upper plots) –C(  ) strength ~ jet S/B –Few % S/B at lowest pT Correlations. h-h Correlations with background subtracted (lower plots)

12 WWND 03/13/06 N Grau12 Different Colliding Systems and Energies Au+Au @ 200 GeV Cu+Cu @ 200 GeV Au+Au @ 62.4 GeV

13 WWND 03/13/06 N Grau13 Parameterize the Away-Side Shape trigg assoc D D Parameterize the away-side shape as a double Gaussian that are offset symmetrically around  =  by fit parameter D. Could be a “bent” jet or a mach/ Cherenkov cone

14 WWND 03/13/06 N Grau14 Au+Au Reaction Plane Dependence (I) Look at 4 th bin since it has the smallest v2. Dip exists at most central before substraction!

15 WWND 03/13/06 N Grau15 Au+Au Reaction Plane Dependence (II) Know v2 depending on triggers RP orientation. Shape independent of RP orientation

16 WWND 03/13/06 N Grau16 Au+Au Reaction Plane Dependence At Higher pT No hint of a volcano shape in any RP bin

17 WWND 03/13/06 N Grau17 For the future: Direct  -h Direct photons not suppressed in the medium. Much less “trigger bias” i.e. less biased toward skin emission Photon measures jet energy  measured away-side D(z) modification  Hadrons PRL 94 232301 (2005)

18 WWND 03/13/06 N Grau18 Inclusive  -h Correlations in Au+Au  C(    : 5-10 GeV/c h: 1-2 GeV/c Comparison with  0 triggered data necessary to extract direct photon correlations.  : 5-10 GeV/c h: 3-5 GeV/c

19 WWND 03/13/06 N Grau19 Comparison of  - and  0 - Triggered Widths Near-side widths are consistent between  -triggered and  0 -triggered. Dominant inclusive photon correlation is decay from jet fragments

20 WWND 03/13/06 N Grau20  -h Near Side Yields PRL 94 232301 (2005) ~50% direct photons above 5 GeV/c in the most central. Also seen in  -triggered near side yield ratio to  0 -triggered yield.

21 WWND 03/13/06 N Grau21 For the future: Non-Photonic e-h Use jet correlations to further understand heavy quark energy loss.

22 WWND 03/13/06 N Grau22 Summary and Conclusions High-p T triggered correlations show –Au+Au away-side that is not broadened –A suppressed yield consistent with punch-through jets. –What is learned from these correlations then? Low-p T triggered correlations show a strongly modified away- side shape –independent of system size and collision energy –Independent of trigger orientation to the RP Still left to do with current data –Further RP studies: Can we show  E ~ L 2,L n ? –Direct  -h: D(z) modification –e-h Correlations: Heavy quark energy loss


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