1. Donald Isenhower - ACU p(d)A Physics in E866/NuSea and PHENIX Donald Isenhower - Abilene Christian University Isenhowe@acu.edu DIS2003 25-April-2003 St. Petersburg, Russia  Review of E866 and results for pp total cross sections  Future Drell-Yan? Plans are in place, but when and where?  Drell-Yan physics & Charmonium suppression in nuclei  Need for p(d)A results for AuAu physics  p(d)A physics in E866/NuSea & comparison to PHENIX  p T broadening & polarization  PHENIX muon system complete for Run 3 - news  Summary

2. Donald Isenhower - ACU FNAL E866/NuSea Collaboration Abilene Christian University Donald Isenhower, Mike Sadler, Rusty Towell, Josh Willis Argonne National Laboratory Don Geesaman, Sheldon Kaufman, Bryon Mueller Fermi National Accelerator Laboratory Chuck Brown, Bill Cooper Georgia State University Gus Petitt, Xiao-chun He, Bill Lee Illinois Institute of Technology Dan Kaplan Los Alamos National Laboratory Tom Carey, Gerry Garvey, Mike Leitch, Pat McGaughey, Joel Moss, Jen-Chieh Peng, Paul Reimer, Walt Sondheim New Mexico State University Mike Beddo, Ting Chang, Vassili Papavassiliou, Jason Webb Oak Ridge National Laboratory Paul Stankus, Glenn Young Texas A & M University Carl Gagliardi, Bob Tribble, Eric Hawker, Maxim Vasiliev Valparaiso University Don Koetke E866/NuSea

3. Donald Isenhower - ACU Forward x F, high-mass spectrometer Solid Be, Fe, W and empty targets Thick absorber wall to filter out all but  ’s Two acceptance defining magnets Four tracking stations and one momentum analyzing magnet Scale 60m long, 3m x 3m at back FNAL E866/NuSea E866/NuSea

4. Donald Isenhower - ACU DY Open Charm Randoms E866/NuSea

5. Donald Isenhower - ACU Ratios of measured Drell-Yan pp and pd cross sections to NLO based on MRST2001 E866/NuSea

6. Donald Isenhower - ACU E866 Drell-yan cross sections per nucleon for selected x F bins E866/NuSea

7. Donald Isenhower - ACU FNAL E866/NuSea Total Cross-section Measurments (PRL submitted and should appear soon, long PRD paper under preparation) FNAL E866/NuSea has measured: First extensive Drell-Yan double-differential cross sections in pp collisions Most precise Drell-Yan cross sections in pd (or pA) collisions Triply-differential cross sections in both pp and pd collisions over a broad kinematic range These results demonstrate: Recent NLO PDF fits provide a reasonable description of antiquark distributions for 0.02 < x < 0.25 Recent NLO PDF fits may overestimate the valence quark distributions at large x (for more on this, see Wu-Ki Tung’s talk at this conference) E866/NuSea

8. Donald Isenhower - ACU Drell-Yan at Fermilab Main Injector Advantages of 120 GeV Experiment Larger Drell-Yan cross section, 7 times larger than at 800 GeV Lower J/  background from beam dump, 7 times smaller These will yield 50 times more events that E866/NuSea Disadvantages: Larger multiple scattering of lower energy muons Poorer mass and x resolution Increased single muon background from hadron decays Shorten target absorber distance Experiment has been approved by FNAL, but is not scheduled to run until 2007-08 E866/NuSea

9. Donald Isenhower - ACU JHF Letter of Intent Physics of High-Mass Dimuon Production at the 50 GeV Proton Synchrotron J.C. Peng et al. What will be measured? Unambiguous establishment of scaling violations in Drell-Yan process Light anti-quark asymmetry via pp and pd Nuclear effects via Drell -Yan Partonic energy loss in nuclei Quarkonium production If polarized proton source: 1. Transversity - correlation between quark momentum and its perpendular spin component 2. Sea quark polarizations

10. Donald Isenhower - ACU E866/NuSea

11. Donald Isenhower - ACU FNAL E906 pA Experimental Program Measure ratio of Drell-Yan yields from d, C, Ca, and W Coverage of Anti- Shadowing and EMC effect regions Better large-x coverage than E772 Antiquark differences in the nucleus E866/NuSea

12. Donald Isenhower - ACU E906 comparison to NMC, E139, and E886 E866/NuSea

13. Donald Isenhower - ACU J/  suppression – an effective signature of Quark-gluon plasma (QGP) formation? Color screening in a QGP would destroy pairs before they can hadronize into charmonium But ordinary nuclear effects also absorb or modify J/  ’s We need a comprehensive understanding of charmonium production in nuclei Competing effects may be identified in p-A collisions by their strong kinematic dependencies, together with complementary studies of Drell-Yan scattering and open-charm production DY  J/  Peng et al, PLB 344 (1995) 1-5. E866/NuSea

14. Donald Isenhower - ACU Modification of parton momentum distributions of nucleons embedded in nuclei e.g. shadowing – depletion of low-momentum partons. Process dependent? Nuclear effects on parton “dynamics” energy loss of partons as they propagate through nuclei and (associated?) multiple scattering effects Production of heavy vector mesons, e.g. J/ ,  ',  production: color singlet or octet ( ) and color neutralization timescale hadronization time: Coherence length for cc fluctuations: absorption on nucleons or co-movers feed-down from higher mass resonances, e.g. χ c Nuclear modification of parton level structure & dynamics Drell-Yan E866 R(W/Be) E772 R(W/D) Ratio(W/Be) 1.0 0.9 0.8 0.7 NMC DIS Drell-Yan Process E866/NuSea

15. Donald Isenhower - ACU Scaling of J/  Suppression? Comparison of 800 GeV (E866) and 200 GeV (NA3) -appears to scale only with x F E866/NuSea: 800 GeV p-A (Fermilab) PRL 84, 3256 (2000) J/  and  ’ similar at large x F where they both correspond to a traversing the nucleus but  ’ absorbed more strongly than J/  near mid-rapidity (x F ~ 0) where the resonances are beginning to be hadronized in nucleus. open charm: no A-dep at mid-rapidity Hadronized J/  E866/NuSea

16. Donald Isenhower - ACU Correction to Nuclear Dependence for p T Acceptance Incomplete coverage in p T can distort J/  suppression versus x F E866/NuSea p T coverage is much better than previous experiment (e.g. E772) because of improved trigger Most significant effects are at lowest x F where p T is cut off near 1 GeV/c Use MC acceptance &  /dp T consistent with our data to correct for incomplete coverage E866/NuSea

17. Donald Isenhower - ACU A universal phenomena seen with, e.g. , p and beams. is ~5 times larger for J/  than for Drell-Yan; cause? gluons interact more strongly than quarks by 9/4 color factor resonances can multiple scatter in final state J/  grows with Radiative energy loss associated with Drell-Yan p T broadening in the BDMS model is tiny P T broadening Summary E866/NuSea

18. Donald Isenhower - ACU Gluon Shadowing for J/  ’s Kopeliovich, Tarasov, & Hufner hep-ph/0104256 Eskola, Kolhinen, Vogt hep-ph/0104124 J.C.Peng, LANL E866/NuSea PHENIX µ + µ - e+e-e+e- PHENIX µ + µ - (Au) In PHENIX µ acceptance for Au-Au collisions? Eskola… : ~ 0.8 Kopeliovich… : ~ 0.4 Strikman… [hep-ph/9812322] : ~ 0.4 PHENIX µ PHENIX e E866 (mid-rapidity) NA50 E866/NuSea

19. Donald Isenhower - ACU Arleo,Gossiaux,Gousset,Aichelin Model (PRC 61, 054906 (2000) & hep-ph/0105047) Absorption of color-octet or –singlet with color neutralizaton times J/ ,  ’ &  c with feed-down Fit to E866/NuSea data with no shadowing & no dE/dx. E866 data J/  ’’ xFxF R(Au/p) y CM ’’ J/  200 GeV p+Au (RHIC) +dE/dx w/o dE/dx p-Au at RHIC: Predictions J/  &  ’ differences at negative rapidity Effect of dE/dx, also at negative rapidity PHENIX Muon Arms pre-resonance fully-formed resonances E866/NuSea

20. Donald Isenhower - ACU Gluon shadowing Gerland, Frankfurt, Strikman, Stocker & Greiner (hep-ph/9812322) Q = 2 GeV 5 GeV 10 GeV.74.4Kopeliovich….87.75w/o anti-shadowing.84.66Eskola….921 No shadowing difference from fixed-target expt. αR“Model” Change due to shadowing for PHENIX μ relative to NA50 for different models to the W/H ratio (R) and the resulting effective α. ( Ratios due to gluon shadowing alone ) E866/NuSea

21. Donald Isenhower - ACU Parton Energy Loss in Nuclei – Kopeliovich Model Johnson, Kopeliovich et al., hep-ph/0105195 Shadowing dE/dx & Shadowing Drell-Yan data from E772 (PRL 64, 2479 (1990)) Shadowing when coherence length, is larger than nucleon separation Three dE/dx mechanisms: String breaking: dE/dz ~ K s ~ 1 GeV/fm Multiple bremstrahlung: dE/dz ~ 3  /  ~.8 GeV/fm Radiative gluon (BDMS):  E ~ 3  /8  ~.075 GeV/fm (since ~ 0.1 GeV 2 from E772) Total  E ~ 2 GeV/fm expected from above From E866 DY data with separation of shadowing & dE/dx via Mass dependence, gives dE/dz ~ 3 ±.6 GeV/fm E866/NuSea

22. Donald Isenhower - ACU Kopeliovich, Tarasov, Hufner hep-ph/0104256 E866 data Full calculation Model: absorption Dynamic calculation of shadowing and of energy loss Also gluon anti-shadowing from Eskola E866/NuSea

23. Donald Isenhower - ACU Upsilon Polarization – E866/NuSea, Phys. Rev. Lett. 86, 2529 (2001) Y 2S+3S has maximal polarization, like Drell-Yan Y 1S has very small polarization Y 1S Y 2S+3S Y 1S Y 2S+3S DY Y 2S+3S Y 1S E866/NuSea

24. Donald Isenhower - ACU Part 2: PHENIX J/  measurement with muon arms in d-Au interactions at √ s NN = 200 GeV

25. Donald Isenhower - ACU The Collaboration A strongly international venture: –12 nations Brazil, China, France, Germany, Hungary, India, Israel, Japan, South Korea, Russia, Sweden, United States  57 institutions

26. Donald Isenhower - ACU The PHENIX Detector e, , h  (Central Arms) –|  | < 0.35,  =  –p T > 0.2 GeV/c  (Muon Arms) –1.2 < |  | < 2.4,  = 2  –p tot > 2 GeV/c Interaction-trigger and vertex Detectors –Beam-Beam Counters (3.0 < |  | < 3.9) –Zero-Degree Calorimeters (|  | > 6.2) –Normalization Trigger Counters (1.1 < |  | < 2.8)

27. Donald Isenhower - ACU Magnet Muon Identifiers Muon 12.5° 35°35° 10.5° 2 Muon Trackers = 2x3 stations 2x3 stations 2 Muon Identifiers = 2x5 planes South Arm: Began operations in 2001-2002 run. North Arm: Installed in 2002. Acceptance : 1.2 < |  | < 2.4  Muon minimum momentum ~ 2 GeV/c Tracking Stations PHENIX Muon Arms

28. Donald Isenhower - ACU MUON IDENTIFIER Small panel Large panel The South Muon Identifier

29. Donald Isenhower - ACU MUON TRACKER Installing a station 2 octant into the south magnet Winding anode wires for a station 3 octant Station 3 octants already installed Station 2 octant under construction

30. Donald Isenhower - ACU End view of Muon Tracker - South

31. Donald Isenhower - ACU Side view of PHENIX detector North Muon Tracker is seen on the right partially exposed

32. Donald Isenhower - ACU Physics Motivations for J/  measurements at RHIC Heavy Ion Physics –Search for the signature of the Quark-Gluon Plasma. J/  yield in heavy ion collisions can be Suppressed due to Debye color screening OR Enhanced due to Recombination –Important to compare J/  yields in Au+Au, p+p (Run 2~) and d+Au (Run-3~) collisions to separate the normal nuclear effects Spin Physics –First direct measurement of the gluon helicity distribution,  G(x), in the proton using double- longitudinal spin asymmetries of the J/  production in polarized p+p collisions (Run-3~) –Understanding of the production mechanism is a key issue  unpolarized p+p data is useful (Run-2~)

33. Donald Isenhower - ACU Need single muon measurement for open charm Measure charm production by D meson semi-leptonic decay, D   K, in d Au collisions. * Good normalization of J/  production. * An important probe of the early stage of heavy ion reactions. * Sensitive to the initial state gluon density in the nuclei. It is difficult to reconstruct D directly, instead we can measure inclusive single muon spectrum. Contributions to the single muon spectrum a) Charm/Beauty decay. b) Pion and Kaon decays - most dominant contribution, especially in low p T regime. c) Other light mesons, such as , we believe their contributions are negligible. d) Drell-Yan di-muons and thermal muons. We consider Pion/Kaon decay contribution as background

34. Donald Isenhower - ACU p+p  J/  X cross sections µ+µ-µ+µ- e+e-e+e- Br (J/  l + l - )  (p+p  J/  X) = 226  36 (stat.)  79 (syst.) nb  (p+p  J/  X) = 3.8  0.6 (stat.)  1.3 (syst.) µb p+p,  s=200GeV Phys. Lett. B390,323 (1997) Our result is consistent with  s scaling from lower energy results Rapidity Fit gives

35. Donald Isenhower - ACU Run-2 pp Preliminary results: South MUTR radiograph: Significant improvements in hardware and software and machine performance since then.

36. Donald Isenhower - ACU Run-3 (dAu): improved performance South MUTR: A new arm installed and operational ! North MUTR: Also, significant MUID and shielding improvements! 2003 Gap-1 Sta-1 Sta-2 Sta-3 Gap-2 Gap-3

37. Donald Isenhower - ACU x F is defined as x F = 2*p z /sqrt(s). With the help of  = m 2 /s, we can obtain x 1 and x 2 : x 1 = 1/2*(x F +sqrt(x F 2 +4*  )); x 2 = x 1 - x F At the large s value of RHIC,  is small, as is therefore also x 2. The x 2 distributions are plotted for simulated J/  's. Kinematics North Central South

38. Donald Isenhower - ACU South M  (GeV/c) Yield (counts) A subset of the data has been analyzed with online code. An order of magnitude improvement of the statistics in the peak should be expected in the real production pass. Trigger and detector eff. are not yet completely determined.

39. Donald Isenhower - ACU North Note: not the same subset of the data as has been processed for the South arm. Direct comparisons between the yield in the two arms are thus meaningless for now. M  (GeV/c) Yield (counts)

40. Donald Isenhower - ACU Summary of lessons from p(d)A Charmonium suppression involves a non-trivial interplay between different effects and involves several timescales including that for hadronizaton and for the coherence of a pair. It has large variations with x F and p T that help reveal the underlying mechanisms p-A (or d-A) measurements serve as a basis for understanding what is seen in nucleus-nucleus collisions and are a must at RHIC. Shadowing is certainly very important at RHIC and must be measured in d-A collisions as soon as possible

41. Donald Isenhower - ACU Summary and outlook for RHIC Run 3 1. J/  peaks have been observed for both muon arms during dAu collisions in Run 3. 2. Production pass to analyze all Run 3 data is to be started RSN. Approximately an order of magnitude more data than presented here should be available. 3. Improving alignment will lead to improved mass resolution 4. Efforts are underway to determine trigger and detector efficiencies throughout the run. 5. Upcoming p-p run (Apr-May) will together with the dAu results also give a baseline for comparisons with the upcoming high statistics Au-Au (Nov - Jun) run.