p d A Physics in E 866 Nu Sea and PHENIX

p(d)A Physics in E 866/Nu. Sea and PHENIX Donald Isenhower - Abilene Christian University Isenhowe@acu. edu DIS 2003 25 -April-2003 St. Petersburg, Russia §Review of E 866 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 Au. Au physics §p(d)A physics in E 866/Nu. Sea & comparison to PHENIX §p. T broadening & polarization §PHENIX muon system complete for Run 3 - news §Summary Donald Isenhower - ACU

FNAL E 866/Nu. Sea 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 Mc. Gaughey, 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 Donald Isenhower - ACU E 866/Nu. Sea

FNAL E 866/Nu. Sea • 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 60 m long, 3 m x 3 m at back Donald Isenhower - ACU E 866/Nu. Sea

DY Open Charm Randoms Donald Isenhower - ACU E 866/Nu. Sea

E 866/Nu. Sea Donald Isenhower - ACU Ratios of measured Drell-Yan pp and pd cross sections to NLO based on MRST 2001

E 866 Drell-yan cross sections per nucleon for selected x. F bins Donald Isenhower - ACU E 866/Nu. Sea

FNAL E 866/Nu. Sea Total Cross-section Measurments (PRL submitted and should appear soon, long PRD paper under preparation) FNAL E 866/Nu. Sea has measured: • First extensive Drell-Yan double-differential cross sections in pp collisions • Most precise Drell-Yan cross sections in pd (or p. A) 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) Donald Isenhower - ACU E 866/Nu. Sea

Drell-Yan at Fermilab Main Injector Experiment has been approved by FNAL, but is not scheduled to run until 2007 -08 Advantages of 120 Ge. V Experiment • Larger Drell-Yan cross section, 7 times larger than at 800 Ge. V • Lower J/ background from beam dump, 7 times smaller These will yield 50 times more events that E 866/Nu. Sea Disadvantages: • Larger multiple scattering of lower energy muons Poorer mass and x resolution • Increased single muon background from hadron decays Shorten target absorber distance Donald Isenhower - ACU E 866/Nu. Sea

JHF Letter of Intent Physics of High-Mass Dimuon Production at the 50 Ge. V 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 Donald Isenhower - ACU

Donald Isenhower - ACU E 866/Nu. Sea

FNAL E 906 p. A 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 E 772 Antiquark differences in the nucleus Donald Isenhower - ACU E 866/Nu. Sea

E 906 comparison to NMC, E 139, and E 886 Donald Isenhower - ACU E 866/Nu. Sea

Peng et al, PLB 344 (1995) 1 -5. DY J/Y J/ suppression – an effective signature of Quark-gluon plasma (QGP) formation? • Color screening in a QGP would destroy charmonium pairs before they can hadronize into • 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 Donald Isenhower - ACU E 866/Nu. Sea

Nuclear modification of parton level structure & dynamics Ratio(W/Be) Drell-Yan NMC DIS Drell-Yan Process 1. 0 0. 9 0. 8 0. 7 E 866 R(W/Be) E 772 R(W/D) 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. χc Donald Isenhower - ACU E 866/Nu. Sea

E 866/Nu. Sea: 800 Ge. V p-A (Fermilab) PRL 84, 3256 (2000) open charm: no A-dep at mid-rapidity Hadronized J/Y? 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 Scaling of J/ Suppression? the resonances are beginning to be • Comparison of 800 Ge. V (E 866) and 200 hadronized in nucleus. Ge. V (NA 3) -appears to scale only with x. F • J/ Donald Isenhower - ACU E 866/Nu. Sea

Correction to Nuclear Dependence for p. T Acceptance • Incomplete coverage in p. T can distort J/ suppression versus x. F • E 866/Nu. Sea p. T coverage is much better than previous experiment (e. g. E 772) because of improved trigger • Most significant effects are at lowest x. F where p. T is cut off near 1 Ge. V/c • Use MC acceptance & d /dp. T consistent with our data to correct for incomplete coverage Donald Isenhower - ACU E 866/Nu. Sea

PT broadening Summary • A universal phenomena seen with, e. g. p, 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 Donald Isenhower - ACU E 866/Nu. Sea

J. C. Peng, LANL PHENIX µ+µ- e+e- Eskola, Kolhinen, Vogt hep-ph/0104124 E 866/Nu. Sea PHENIX µ PHENIX e Kopeliovich, Tarasov, & Hufner E 866 (mid-rapidity) hep-ph/0104256 NA 50 Gluon Shadowing for J/ ’s In PHENIX µ acceptance for Au-Au collisions? • Eskola… : ~ 0. 8 • Kopeliovich… : ~ 0. 4 • Strikman… [hep-ph/9812322] : ~ 0. 4 PHENIX µ+µ- (Au) Donald Isenhower - ACU E 866/Nu. Sea

Arleo, Gossiaux, Gousset, Aichelin Model E 866 data J/Y (PRC 61, 054906 (2000) & hep-ph/0105047) • Absorption of color-octet or –singlet with color neutralizaton times fully-formed resonances • J/Y, Y’ & cc with feed-down • Fit to E 866/Nu. Sea data with no shadowing & no d. E/dx. pre-resonance Y’ PHENIX Muon Arms J/Y R(Au/p) p-Au at RHIC: Predictions • J/ & ’ differences at negative rapidity • Effect of d. E/dx, also at negative rapidity x. F Y’ w/o d. E/dx 200 Ge. V p+Au (RHIC) y. CM J/Y +d. E/dx y. CM Donald Isenhower - ACU E 866/Nu. Sea

Gluon shadowing Gerland, Frankfurt, Strikman, Stocker & Greiner (hep-ph/9812322) 10 Ge. V Change due to shadowing for PHENIX μ relative to NA 50 for different models to the W/H ratio (R) and the resulting effective α. “Model” R 1 . 92 Eskola… . 66 . 84 w/o anti-shadowing . 75 . 87 Kopeliovich… . 4 . 74 Q = 2 Ge. V α No shadowing difference from fixed-target expt. 5 Ge. V (Ratios due to gluon shadowing alone) Donald Isenhower - ACU E 866/Nu. Sea

Parton Energy Loss in Nuclei – Kopeliovich Model Johnson, Kopeliovich et al. , hep-ph/0105195 Shadowing when coherence length, is larger than nucleon separation Shadowing Three d. E/dx mechanisms: • String breaking: d. E/dz ~ Ks ~ 1 Ge. V/fm • Multiple bremstrahlung: d. E/dz ~ 3 a /p ~. 8 Ge. V/fm d. E/dx & Shadowing • Radiative gluon (BDMS): DE ~ 3 a /8 D ~. 075 Ge. V/fm (since ~ 0. 1 Ge. V 2 from E 772) Total DE ~ 2 Ge. V/fm expected from above From E 866 DY data with separation of shadowing & d. E/dx via Mass dependence, gives d. E/dz ~ 3 ±. 6 Ge. V/fm Drell-Yan data from E 772 (PRL 64, 2479 (1990)) Donald Isenhower - ACU E 866/Nu. Sea

Kopeliovich, Tarasov, Hufner hep-ph/0104256 Model: • absorption • Dynamic calculation of shadowing and of energy loss • Also gluon anti-shadowing from Eskola E 866 data Full calculation Donald Isenhower - ACU E 866/Nu. Sea

Upsilon Polarization – E 866/Nu. Sea, Phys. Rev. Lett. 86, 2529 (2001) DY Y 2 S+3 S Y 1 S Y 2 S+3 S DY Y 2 S+3 S Y 1 S • Y 2 S+3 S has maximal polarization, like Drell-Yan • Y 1 S has very small polarization Donald Isenhower - ACU E 866/Nu. Sea

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

The PHENIX Detector • e, , h (Central Arms) • (Muon Arms) • Interaction-trigger and vertex Detectors – | | < 0. 35, = – p. T > 0. 2 Ge. V/c – 1. 2 < | | < 2. 4, = 2 – ptot > 2 Ge. V/c – Beam-Beam Counters (3. 0 < | | < 3. 9) – Zero-Degree Calorimeters (| | > 6. 2) – Normalization Trigger Counters (1. 1 < | | < 2. 8) Donald Isenhower - ACU

PHENIX Muon Arms 2 Muon Trackers = 35° 2 x 3 stations 2 Muon Identifiers 12. 5° = 2 x 5 planes South Arm: Began operations in 2001 -2002 run. North Arm: Installed in 2002. Acceptance : 1. 2 < | | < 2. 4 Muon minimum momentum ~ 2 Ge. V/c Tracking Stations 35° Muon 10. 5° Magnet Muon Identifiers Donald Isenhower - ACU

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

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

End view of Muon Tracker - South Donald Isenhower - ACU

Side view of PHENIX detector North Muon Tracker is seen on the right partially exposed 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 doublelongitudinal 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~) 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 Donald Isenhower - ACU

p+p J/ X cross sections Phys. Lett. B 390, 323 (1997) p+p, s=200 Ge. V e+ eµ+ µ- Rapidity Fit gives 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 • Our result is consistent with s scaling from lower energy results Donald Isenhower - ACU

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

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

Kinematics x. F is defined as x. F = 2*pz/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. North Central South Donald Isenhower - ACU

South 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. Yield (counts) Donald Isenhower - ACU M + -(Ge. V/c)

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. Yield (counts) M + -(Ge. V/c) 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 Donald Isenhower - ACU

Summary and outlook for RHIC Run 3 1. J/ peaks have been observed for both muon arms during d. Au 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 d. Au results also give a baseline for comparisons with the upcoming high statistics Au-Au (Nov -Jun) run. Donald Isenhower - ACU