Recent Quarkonia Results from PHENIX

Abhisek Sen, Georgia State University

for the PHENIX collaboration

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Probing the medium with Quarkonia

Quarkonium dissociation is suggested as a thermometer for the medium created at heavy ion collisions.

Highlights of recent quarkonia results from PHENIX J/ψ feed down measurement (p+p). d+Au CNM reference at 200 GeV. J/ψ measurement from Au+Au at 200 , 62 & 39 GeV. Upsilon measurements (p+p and d+Au).

Mocsy & PetreczkyPRL. 99, 211602 (2007)

Di-leptons in p+p

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Midrapidity |y|<0.35 Forward Rapidity 1.2 < |y| <2.2

PHENIX has excellent capabilities of measuring different quarkonia states in di-electron and di-muon channels.

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J/ψproduction at p+p

PRL 98, 232002 (2007)

Total J/ψ cross-section : 181 +/- 22 nb (stat. + sys.) ArXiv: 1105.1966v1

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J/ y feed down measurement

ArXiv: 1105.1966v1

c →J/y +

= 9.6 +/- 2.4%

= 32 +/- 9 %

y’→ e+e-

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J/ψ suppression in Au+Au 200 GeV

arXiv: 1103:6269

Enough temperature to melt ψ’ and C according to lattice calculations.

An extreme case :

Total J/ψfeed-down : 42 +/- 9 %

New forward data from 2007 with finer binning and lower systematics.

Npart

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J/ψ suppression in Au+Au 200 GeV

arXiv: 1103:6269

Historic Puzzle

Suppression is stronger at forward rapidity than mid-rapidity.

Suppression in mid-rapidity is comparable to that measured at SPS

energies.

No obvious pattern of the suppression with energy density.

NA50, 17.2 GeV

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Probing Cold Nuclear Matter Effects

d AuPHENIX can probe all Bjorken x range where EPS09 predicts Suppression at shadowing region. Suppression-enhancement transition Enhancement at anti-shadowing region.

PHENIX high statistics d+Au dataset from 2008 is now

analyzed.

LO

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J/ψ suppression in d+Au

(Solid Red curves) A reasonable aggreement with EPS09 nPDF + sbr = 4 mb .

(Dashed green line) CGC calculations can’t reproduce mid-rapidity. (Nucl. Phys. A 770(2006) 40)

arxiv:1010.1246

y

What about RCP ?

EPS09 with assumed linear thickness dependence fails to describe centrality dependence of forward rapidity region.

Geometry integrated EPS09 is in agreement with geometry integrated (MB) data.

Lets arbitrarily give EPS09 a linear geometry dependence

(Solid red curves) A reasonable agreement with EPS09 nPDF + sbr = 4 mb for central collisions but not peripheral.

(Dashed green line) CGC calculations can’t reproduce mid-rapidity. (Nucl. Phys. A 770(2006) 40)

d+Au Geometry dependence

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1( ) ( , )T Tr dz z r

Nuclear geometry via density-weighted longitudinal thickness

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Woods-Saxon

• Break-up has exponential dependence.• EPS09 has unknown dependence.

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RdAu with geometry

The forward rapidity points suggests a quadratic or higher geometry dependence.

For any value of a, we can put a point in the RCP(a) - RdAu(a) plane.

Ellipses are systematic uncertainties.

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New pT dependence of RdAu

RdAu at midrapidity |y|<0.35.

Convoluted shadowing + Cronin effect.

Proper geometry dependence of shadowing needed.

See Darren McGlinchey’s Poster

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Energy dependence of J/ψproduction for Au+Au.

New: J/ψfrom Au+Au 62 and 39 GeV

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In 2010 PHENIX collected 700M (200M) MB events from 62.4 GeV (39 GeV) Au+Au collision.

Rapidity 1.2 <|y| <2.2

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Energy dependence of J/ψ RCP

PHENIX doesn’t have a p+p reference at 62 and 39 GeV. RCP will give us an insight about the suppression level. Suppression is of similar level at all energies. Accounting for energy dependence of CNMs is critical for interpreting these results.

Rapidity 1.2 <|y| <2.2

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Energy dependence of CNMs

JHEP 0902:014 (2009)

RG for J/ψ production at RHIC

o Proper geometry dependence need to be included.o Reduce uncertainties by measuring d+Au at the same energy.

A systematic analysis at y~0 using EKS98 + σbreakup showed a clear collision energy dependence of σbreakup.

1.2 < y < 2.2|y| < 0.35-2.2 < y < -1.2

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’s in p+p collisions at 200 GeV

|y|<0.35 1.2 < |y| <2.2-2.2 < y <-1.2

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New PHENIX results

d Au

d+Au Au+Au

RAA Coming soon!Coming soon RdAu at mid-rapidity

First measurement of CNM effects in production at RHIC.

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Summary

Total J/ y feed down from y’ and C at 200 GeV at midrapidity is 42 +/- 9% in p+p.

CNM effects are a large fraction of the observed Au+Au suppression and extrapolation from d+Au to Au+Au is imperative.

Geometry dependence of shadowing is stronger than linear.

Measured Au+Au J/y suppression at 200, 62 and 39 GeV.

Measured upsilon suppression in d+Au collisions.

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BACK-UPs

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Model comparison

Projection of EPS09 shadowing and sbr to Au+Au collision in mid-rapidity and forward-rapidity doesn’t reproduce RAA or the ratio between rapidities.

Combine x-dependent nuclear absorption (but sbr=0 at midrapidity) with hot, dissociative comoving medium (sco=0.65mb).

arXiv: 1103:6269

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Cold nuclear matter effects(CNM)

Need to understand nuclear affects without any hot medium( a.k.a CNM).

J/ψfrom p+Au or d+Au is a excellent probe to understand this effects.

Nuclear PDFs known to be modified at various x ranges. shadowing, anti-shadowing, EMC effects etc.

PHENIX can probe both shadowing and anti-shadowing region with detectors at forward y, x~0.005 mid y, x~0.03 backward y, x~0.1

d Au

K.J. Eskola et al. Nucl. Phys. B535 (1998) 351

anti-shadowing

shadowing

(Solid Red curves) A reasonable aggreement with EPS09 nPDF + sbr = 4 mb .

(Dashed green line) CGC calculations by Kharzeev and Tuchin (Nucl. Phys. A 770(2006) 40), includes gluon saturation at low x explains forward rapidity.

Forward Weekly Meeting 23

A COLLECTION OF SELECTED RESULTS

5/9/11

Available Data Sets

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PHENIX detector configurations

RPC1

Central arms:Hadrons, photons, electrons• J/y→ e+e-; y’ → e+e-; c → e+e-;• |η|<0.35• pe > 0.2 GeV/c• Δφ=π(2 arms x π/2)

Forward rapidity arms:Muons• J/y→ μ+μ- ; → μ+μ-

• 1.2<|η|<2.2• pμ > 1 GeV/c• Δφ = 2π