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Recent Heavy Ion Results from PHENIX. Carla M Vale Brookhaven National Laboratory for the PHENIX Collaboration September 23 2010. Single spectra From 0 to multiple particle ID Expand to higher p T v 2 at high p T and azimuthal dependence of R AA. Two -particle correlations
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Recent Heavy Ion Results from PHENIX Carla M Vale Brookhaven National Laboratory for the PHENIX Collaboration September 23 2010
Single spectra From 0 to multiple particle ID Expand to higher pT v2 at high pT and azimuthal dependence of RAA Two-particle correlations Expand range of trigger and associate Azimuthal dependence -hadron correlations Outline Overview of PHENIX’s experimental contributions towards the understanding of energy loss, focusing on recent publications and results • Jet reconstruction • Spectra • RAA PHENIX Results, Carla M Vale
PHENIX in 2010 Crossed the Petabyte frontier! Final run with HBD and RXNP Installation of SVX now ongoing PHENIX Results, Carla M Vale
Single hadron spectra PHENIX Results, Carla M Vale
PHENIX RAA for identified particles The variety and precision of results keep expanding, revealing interesting features • 0, • photons • heavy flavor from e± • K±, , PHENIX Results, Carla M Vale
RAA at high pT is well described by several theoretical frameworks, with differing assumptions/ingredients The 0 dilemma Solution: Add more data to the picture, going from simpler to more differential PHENIX Results, Carla M Vale
Extend experimental range: At pT ~ 15 GeV and above, 0 measurement limited by systematic uncertainties due to merging of the two photon showers in the calorimeter; for , this is not the case until pT ~ 50 GeV PRC82, 011902 (2010) arXiv:1005.4916 Trend for is consistent with 0; Linear fits indicate RAA slowly rises or is flat with pT; Measurement is still statistically limited: future improvements PHENIX Results, Carla M Vale
RAA for arXiv:1004.3532 • Suppression for starts out weaker than for 0 and , but approaches it at high pT; K± at low pT seem to follow same trend as • Npart scaling seen for Cu+Cu (not shown) • Binary scaling applies in d+Au: no evidence of cold nuclear matter effects (not shown) PHENIX Results, Carla M Vale
Azimuthal asymmetry PHENIX Results, Carla M Vale
0 v2 at high pT arXiv:1006.3740 • Non-zero v2 even at high pT • The measured v2 at high pT is not a result of the hydrodynamical anisotropy, but arises from the dependence of the energy loss on the amount of medium that the partons have to traverse look at RAA () PHENIX Results, Carla M Vale
RAA in-plane vs. out-of-plane pT RAA Npart • Out-of plane RAA nearly flat with centrality at low pT • In- and out-of-plane converge at high-pT (~10GeV/c) PHENIX Results, Carla M Vale
Comparing with models Stronger path length dependence better agreement HT, ASW, AMY comparisons: S.Bass et al in arXiv:0808.0908 AdS/CFT: Marquet and Renk in arXiv:0908.0880 PHENIX Results, Carla M Vale
Di-hadron PHENIX Results, Carla M Vale
0-hadron correlations PRL104, 252301 (2010) arXiv:1002.1077 • Near side: • width matches p+p, yield enhanced at low pT • Away side: • low pT: broad non-gaussian peak • for high trigger and associated pT, away side peak is suppressed but shape is consistent with p+p PHENIX Results, Carla M Vale
Away-side IAA At high pT, head region and full away side IAA consistent: no shape modification IAA larger than 0 RAA: surface bias balanced by away-side spectrum being softer than single inclusive hadron PHENIX Results, Carla M Vale
0-h azimuthal dependence Check how per-trigger yields change as a function of the angle between trigger and the reaction plane: test path-length dependence PHENIX Results, Carla M Vale
Near side yield Near side yields nearly constant when going from in- to out-of-plane PHENIX Results, Carla M Vale
Away side yield Away side yields drop from in-plane to out-of-plane: clear path-length dependence PHENIX Results, Carla M Vale
-jet PHENIX Results, Carla M Vale
Direct - h correlations • g insensitive to strong interaction no surface bias, can probe the entire geometry • well calibrated, Eg ~ Ejet (to leading order) PHENIX Results, Carla M Vale
-h away-side Same level of suppression as in 0 RAA and 0-h IAA PHENIX Results, Carla M Vale
Fragmentation functions in p+p and Au+Au p+p slope: 6.89 0.64 Au+Au slope: 9.49 1.37 PHENIX Results, Carla M Vale
Jet reconstruction PHENIX Results, Carla M Vale
Full jet reconstruction • Gaussian filter method: cone-like, but no hard angular cut-off • Analysis performed in p+p and Cu+Cu events • Fake rejection essential in heavy ion environment PHENIX Results, Carla M Vale
Jet spectra in p+p Spectra and fragmentation functions in p+p consistent with NLO and PYHIA PHENIX Results, Carla M Vale
Jet RAA in Cu+Cu Similar to 0 RAA value Consistent with flat pT dependence PHENIX Results, Carla M Vale
Summary & Outlook • First decade of RHIC running completed • Shifting from making new measurements to increasing precision and constraining theory • Putting together a full picture of energy loss through developments in several directions: higher pT, (multi-)particle ID, correlations and full jet reconstruction • HBD Au+Au run this year: results coming soon • About to start the era of upgrades • Silicon Vertex detector installation ongoing • FVTX to follow • Already planning for the next decade… PHENIX Results, Carla M Vale
Counts per 2.5 GeV bin in 50B AuAu Events Central Arm upgrade: 2, = 1 SVX +FVTX + More Si Tracking layers + Compact EMCal + Solenoidal Magnet + Hcal + High speed/bandwidth DAQ NLO pQCD (W. Vogelsang) CTEQ6M5, DSS FF pp @ 200 GeV |h|<1.0 q,g jets Direct g Fragmentation g p0(assume RAA = 0.2) p0 GEANT4: Q-Pythia Dijet Event Photons Jets The Future: sPHENIX PHENIX Results, Carla M Vale