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J/ y results from PHENIX

J/ y results from PHENIX. Abhisek Sen, Georgia State University for the PHENIX collaboration Fluctuations, Correlations and RHIC Low Energy Runs BNL, USA October 5, 2011. Probing the medium with Quarkonia.

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J/ y results from PHENIX

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  1. J/y results from PHENIX Abhisek Sen, Georgia State University for the PHENIX collaboration Fluctuations, Correlations and RHIC Low Energy Runs BNL, USA October 5, 2011

  2. Probing the medium with Quarkonia • Quarkonium dissociation is suggested as a thermometer for the medium created at heavy ion collisions. • J/ψ suppression in heavy ion collisions due to color screening if QGP is formed was proposed by Matsui & Satz [PLB 178, 416(1986)] which has not been exclusively verified by experiments to date. Mocsy & Petreczky PRL. 99, 211602 (2007)  P. Petreczky, 1001.5284

  3. PHENIX detector configurations • 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 RPC1

  4. 200 GeV Results

  5. Di-leptons in p+p 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.

  6. J/ψproduction at p+p Total J/ψ cross-section : 181 +/- 22 nb ArXiv: 1105.1966v1

  7. J/yfeed down measurement c→J/y+  = 9.6 +/- 2.4% ArXiv: 1105.1966v1 = 32 +/- 9 %

  8. J/ψsuppression in Au+Au 200 GeV Puzzle: Suppression is stronger at forward rapidity than mid-rapidity. arXiv: 1103:6269 (accepted to PRC yesterday)

  9. Understanding J/ψsuppression in Au+Au Total J/ψfeed-down : 42 +/- 9 % An extreme case : Enough temperature to melt ψ’ and Caccording to lattice calculations.

  10. Comparison with other energies

  11. Adding more to the puzzle NA50, 17.2 GeV No obvious pattern of the suppression with energy density.

  12. Available Data Sets PHENIX LOW ENERGY DATASET • Good for J/ψanalysis. • Not enough J/ψstatistics.

  13. J/ψfrom Au+Au 62.4 GeV and 39 GeV • In 2010 PHENIX collected 700M (200M) MB events from 62.4 GeV (39 GeV) Au+Au collision. • Total No of J/ψ’s • 62 GeV: 1130.4 +/- 172.7(stat) • 39 GeV: 169.1 +/- 82.7(stat) 62 GeV Accptance Weighted fit: RED : Total fit, BLACK: Double Gaussian components for J/Y , BLUE: Exponential component, GREEN: Low mass peak fit component. 39 GeV

  14. J/ψ Invariant yields in Au+Au collision Rapidity 1.2 <|y| <2.2

  15. Energy dependence of J/ψRCP Rapidity 1.2 <|y| <2.2 • 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 within uncertainties.

  16. Quarkonia Suppression Similarity in √s Overall suppression of J/ψ is nearly “similar” between RHIC, SPS, & LHC ? PHENIX y=0 SPS PHENIX forward CMS - pT > 6.5 39 GeV 62 GeV

  17. A Recipe for Suppression The Ingredients: CNM effectsshadowing, gluon saturation, nuclear absorption, initial-state parton energy loss HNM effectsdissociation, regeneration But what are the proportions? How they depend on energy? Is centrality is a good variable for comparison?

  18. Few CNM effects in Quarkonia production Traditional shadowing from fits to DIS or from coherence models anti-shadowing RG in Au shadowing Absorption (or dissociation) of into two D mesons by nucleus or co-movers Note: Gluon shadowing affects the underlying charm yield. Absorption reduces the fraction of charm forming bound charmonium. There are other possible mechanisms that modify quarkonium production. Initial state energy loss and Cronin effect are examples.  Start by looking at CNM effects using d+Au collisions.

  19. J/ψsuppression in d+Au Geometry integrated EPS09 is in agreement with MB centrality integrated data. • (Solid Red curves) A reasonable aggreement 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) • (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) y What about Rcp ? EPS09 with assumed linear thickness dependence fails to describe centrality dependence of forward rapidity region. Au d Lets arbitrarily give EPS09 a linear geometry dependence PhysRevLett.107.142301

  20. d+Au Geometry dependence Nuclear geometry via density-weighted longitudinal thickness Woods-Saxon • Break-up has exponential dependence. • EPS09 has unknown dependence.

  21. RdAuwith geometry For any value of a, we can put a point in the RCP(a) - RdAu(a) plane. Ellipses are systematic uncertainties. The forward rapidity points suggests a quadratic or higher geometry dependence.

  22. CNM extrapolation in Au+Au • 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. • Picture is more complex today with strong cold nuclear matter effects and different hot nuclear suppression.

  23. Energy dependence of CNMs A systematic analysis at y~0 using EKS98 + σbreakup showed a clear collision energy dependence of σbreakup. RG for J/ψ production at RHIC 1.2 < y < 2.2 |y| < 0.5 -2.2 < y < -1.2 JHEP 0902:014 (2009) Work in progress

  24. PHENIX Run Plan

  25. Summary • Similar J/y suppression at 200, 62 and 39 GeV at Au+Au collision, when looking at centrality dependence. • 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. • CNM effects not same at all energies. Need a consistent study of different nuclear matter effects to understand the suppression.

  26. BACK-UP

  27. PHENIX Muon-Arm g+g -> J/y Rapidity 1.2 <|y| <2.2

  28. PHENIX Muon Arm performance J/y acc*eff at 62 GeV Au+Au Dimuon mass acceptance Input: Flat Mass, Pt, rapidity Muon Tracker performance at Run10

  29. low x Energy loss of incident gluon shifts effective xF and produces nuclear suppression which increases with xF high x R(A/p) R=1 xF Few CNM effects in Quarkonia production Traditional shadowing from fits to DIS or from coherence models anti-shadowing RG in Au shadowing Absorption (or dissociation) of into two D mesons by nucleus or co-movers Gluon saturation from non-linear gluon interactions for the high density at small x; amplified in a nucleus. p A  Start by looking at CNM effects using d+Au collisions.

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