Highlights from PHENIX II: Photons and Leptons

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Highlights from PHENIX IIPhotons and Leptons

• Terry Awes, ORNL
• For the PHENIX collaboration

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Photons and Leptons

• Penetrating probes that carry information about
  their production.
• Rare processes
• Need large data samples
• Large backgrounds
• Need precise background determination
• Background ? from decays of ?? and ?
• Electrons from ? conversions
• Combinatorial Backgrounds
• Theme Towards Higher Accuracy

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More Precise Measurements
?? AuAu 200 GeV (Run 4)

• Improved Statistical errors
• AuAu Statistics
• 30 10 1
• ( Runs 7 4 2 )
• Improved Systematic errors
• More statistics
• Two EMCals

arXiv0801.4020
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Improved pp Reference Data
?? pp 62 GeV (Run 6)
J.Phys.G31S491 (2005)

• PHENIX 62 GeV pp ?? cross section approx. 2
  times higher than ISR average.
• 200 GeV pp data 10x (with Run5)

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Nuclear Suppression Dependence on
Energy
Particle Species
?? CuCu 22,62,200 GeV (Run 5)
?? AuAu 200 GeV (Run 4)
g
?
??
?
arXiv0801.4555

• Model calculations indicate quenching expected at
  ?sNN 22 GeV, but Cronin effect dominates
• Species dependence to probe space/time of
  suppression

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Dependence of Nuclear Suppression
NPart
Pathlength
PHENIX PRC 76 034904

• RAA scales with Npart at same ?sNN
• Some indication for higher order effects
• Approximate scaling with lt?Lgt
• Use RAA(Npart, ?sNN, Species, Pathlength) to
  illuminate models

Session I Klaus Reygers
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Direct Photons
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Towards inclusive ? (? contribution)
???? AuAu 200 GeV
Poster B.Sahlmuller
???? pp systematics
PHENIX Preliminary
PRC 75, 024909 (2007)
PRC 75, 024909 (2007)

• Universal ???? mT-scaling
• Independent of centrality in AuAu

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Direct ? AuAu ?Direct ?Inclusive-?Decay

• Run 2 No ? suppression -gt Jet quenching (PRL 94,
  232301 (2005)).

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Direct ? RAA Results
Central CuCu 200 GeV (Run 5)
Direct ? RAA vs Npart
PHENIX Preliminary
Min Bias AuAu 62 GeV (Run 4)
PHENIX Preliminary
Session VIII Takao Sakaguchi

• Direct ? RAA ? 1
• Is there other evidence for nuclear effects?
• Reduced/enhanced radiation due to jet quenching

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Direct ? v2 AuAu 200 GeV
Direct ? v2 Min Bias AuAu 200 GeV (Run 4)

• Interested in sign of direct ? v2 (at high pT)
• Positive parton emission quenched
• Negative parton emission (Brems.) enhanced
• Results suggest positive v2

Session XV Kentaro Miki
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?-h Correlations
Session XV Matthew Nguyen

• ? measures recoil parton momentum
• Measure fragmentation function D(Z)

?-h pp 200 GeV (Run 5)
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J/? Production
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J/? dAu Cold Nuclear Matter
J/? RdAu 200 GeV

• Increased Run 5 pp statistics (x10 Run 3)
• Improved consistent pp and dAu analysis
• Improved alignment, resolution, yield
  extraction,
• Cancellation of systematic errors in RdAu
• Result CNM Shadowing(EKS) ?Breakup 2.8
  mb
• Consistent within errors with previous results
• and with ?Breakup4.2/-0.5mb (SPS result)

1.7 -1.4
arXiv0711.3917
Session VI Matthew Wysocki
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J/? AuAu CNM Effects
J/? RAuAu 200 GeV (Run4)
1.2 lt y lt 2.2
arXiv0711.3917

• Large errors still (need Run 8 dAu, Run 7 AuAu)
• Comparison suggests more forward suppression
  beyond CNM than at mid-rapidity
• BUT models shown dont describe RdAu impact
  parameter dependence

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J/? RAA CuCu and AuAu
J/? RAA 200 GeV

• Approx 2x more J/? in CuCu sample than AuAu
  sample
• More precise Npartlt100 info
• Curves show RAA prediction from ad hoc CNM fit to
  RdAu separately at y0 and y gt 1.2
• CNM from RdAu fit describes suppression for Npart
  lt 100.

Session XVIII Susumu Oda

• RdAu constraints are not sufficient to say if
  suppression beyond cold nuclear matter is
  stronger at forward rapidity

arXiv0801.0220
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J/? ltpT2gt CuCu and AuAu
arXiv0801.0220

• No (or modest) pT broadening of J/?
• Conspiracy of low pT suppression and
  recombination?

Session XVIII Susumu Oda
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Low Mass ee-
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Electron Pair Mass Spectrum pp
Mee pp 200 GeV (Run5)
Unlike sign

• Combinatorial Bkground subtraction error 0.25
• Confirmed with special convertor runs
• Correlated unlike (and like) pairs due to jet and
  Dalitz photon pair conversions

Like sign
arXiv0801.0220
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Hadronic Cocktail to Calculate Mee

• Based on PHENIX measurements
• (Light VM See Session XXIII Y. Nakamiya)
• Fit to pion spectrum provides excellent fit to
  all other mesons with MT-scaling assumption
• MT-scaling works very well

arXiv0802.0050
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Measured pp Mee compared to Cocktail

• Cocktail filtered in PHENIX acceptance
• Charm, Bottom, DY contributions from PYTHIA
• Excellent agreement!

arXiv0802.0050
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Heavy Quarks in pp from ee-
After subtraction of Cocktail -
Fit to acharm bbottom (with PYTHIA shape)

• Good agreement with single e results
• Also new analyses via e-h coincidences, single
  muons, and direct charm measurement
• See talks

Session XIV Yuhei Morino Donny Hornback
arXiv0802.0050
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Bottom Measurement
pp 200 GeV Charm and bottom extracted via e-h
mass analysis
Session XIV Yuhei Morino

• Charm and bottom spectra both ?x? above FONLL
  calculations
• But ratio is in good agreement with FONLL

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Heavy Flavor via non-photonic Electrons

• HF strongly suppressed, Significant v2
• Implies high density, small diffusion coefficient
• Estimate ?/s (1.3-2)/4?
• Very close to conjectured limit

Session XIV Ralf Averbeck
PHENIX PRL98, 172301 (2007)
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AuAu Mee compared to Cocktail

• Data and Cocktail absolutely normalized
• Cocktail normalized to AuAu measurements
• Except ccbar
• Low mass excess
• 150 lt Mee lt 750
• X 3.40.2(stat.) 1.3(syst.)0.7(model)
• Intermediate mass agreement

arXiv0706.3034
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PT Dependence of AuAu Mee

• Low Mass excess is a low pT enhancement
• Huge excess at lowest pT
• Late Phase info

PHENIX Preliminary
Session XI Alberica Toia
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High pT Direct ? Yield from ?

• Virtual ??with pT gtgt mee should be produced
  directly with a rate and mass distrib. that
  follows a Dalitz form fdir with MHad-gtoo
• Extract Direct ? excess as fraction r of fdir
  needed to describe low mass excess
• That direct ? fraction of inclusive ? (mostly
  ???and ?) should be the same as the real ?
  fraction of inclusive ?? (mostly ???and ?)

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Direct ? via ? for pp, AuAu

• New pp result with ? method agrees with NLO
  pQCD predictions, and with statistical method at
  high pT
• Confirmation of the method
• For AuAu (QM05 result) there is a significant
  low pT excess above pp expectations
• Interpreted as thermal emission -gt Initial T

Session XV Torsten Dahms
arXiv0801.xxxx
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Summary

• More precise studies of sQGP matter
• Systematics of RAA

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PHENIX Data Sets