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Charming Measurements in E866/NuSea

Charming Measurements in E866/NuSea. Mike Leitch - Los Alamos National Laboratory leitch@lanl.gov. Charm Production: from Threshold via SPS to RHIC and LHC European Center for Theory, June 17-22, 2002. E772 - 1991. Introduction to Physics of Drell-Yan & Charmonium suppression in nuclei

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Charming Measurements in E866/NuSea

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  1. Charming Measurements in E866/NuSea Mike Leitch - Los Alamos National Laboratory leitch@lanl.gov Charm Production: from Threshold via SPS to RHIC and LHC European Center for Theory, June 17-22, 2002 E772 - 1991 • Introduction to Physics of Drell-Yan & Charmonium suppression in nuclei • E866/NuSea & comparison to NA50 • pT broadening & polarization • Summary Mike Leitch - LANL

  2. Nuclear modification of parton level structure & dynamics Drell-Yan Drell-Yan Process Ratio(W/Be) 1.0 0.9 0.8 E866 R(W/Be) NMC DIS E772 R(W/D) 0.7 • 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/Ψ, Ψ ',  • 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 Mike Leitch - LANL

  3. Peng et al, PLB 344 (1995) 1-5. DY  J/Y • J/Ψ 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/Ψ’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 Mike Leitch - LANL

  4. 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 UniversityGus Petitt, Xiao-chun He, Bill LeeIllinois Institute of Technology Dan KaplanLos Alamos National LaboratoryTom 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 WebbOak Ridge National Laboratory Paul Stankus, Glenn YoungTexas A & M UniversityCarl Gagliardi, Bob Tribble, Eric Hawker, Maxim VasilievValparaiso UniversityDon Koetke Mike Leitch - LANL

  5. FNAL E866/NuSea • Forward xF, high-mass spectrometer • Solid Be, Fe, W and empty targets • Thick absorber wall to filter out all but μ’s • Two acceptance defining magnets • Four tracking stations and one momentum analyzing magnet • Scale 60m long, 3m x 3m at back Mike Leitch - LANL

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

  7. PT Broadening at 800 GeV E772 & E866: p-A at 800 GeV Upsilons Drell-Yan a(pT) shape is independent of xF & same for NA3 at a lower energy (curves are with A slightly different for each) J/Y & Y’ Mike Leitch - LANL

  8. Comparison to NA50 J/Ψ Nuclear Dependence yCM : -0.4 1.0 p-p & p-d E866 800 GeV J/Y NA50/51 450 GeV Y’ Charmonia cross sections from NA50/51 for p-A collisions at 450 GeV/c • ay~0 dependence? • gluon shadowing? • change in production, e.g. octet vrs singlet balance? • (Both experiments have good pT coverage, so strong pT-dependence of α not the cause) * mid-rapidity part of E866 data Mike Leitch - LANL

  9. J/Y Deuterium/Hydrogen Ratios Preliminary A = 1.2 A = 1.35 A = 2 A = 2 Preliminary Using fits to E866/NuSea p + Be, Fe, W data: Mike Leitch - LANL

  10. J.C.Peng, LANL Eskola, Kolhinen, Vogt hep-ph/0104124 PHENIX μ+μ- E866/NuSea e+e- PHENIX μ PHENIX e E866 (mid-rapidity) NA50 Kopeliovich, Tarasov, & Hufner hep-ph/0104256 Gluon Shadowing for J/Ψ’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) Mike Leitch - LANL

  11. PT Broadening for different energies and probes – other data NA10 140,286 GeV p- DY PLB 193, 368 (1987) E288 400 GeV p DY PRD 23, 604 (1981) E537 125 GeV p,p- J/Y PRL 60, 2121 (1988) Omega 39.5 GeV p- J/Y PL110B, 415 (1982) Antipov, 43 GeV p- J/Y PL76B, 235 (1978) Mike Leitch - LANL

  12. Systematics of PT Broadening Mike Leitch - LANL

  13. Feeding of J/Ψ’s from Decay of Higher Mass Resonances E705 @ 300 GeV/c, PRL 70, 383 (1993) • Large fraction of J/Ψ’s are not produced directly • Nuclear dependence of parent resonance, e.g. χC is probably different than that of the J/Ψ • e.g. in proton production ~30% of J/Ψ’s will have effectively stronger absorption because they were actually more strongly absorbed (larger size) χC’s while in the nucleus Mike Leitch - LANL

  14. Open Charm Nuclear Dependence : xF Dependence? E769 250 GeV ± PRL 70,722 (1993) WA82 340 GeV - PRB 284,453 (1992) Vogt et al., NP 383,643 (1992) E769 250 GeV - E789 : PRL 72, 2542 (1994) 800 GeV p + A, <xF> = 0.03 a = 1.02±.03±.02 WA78 320 GeV - (Beam dump) Mike Leitch - LANL

  15. Ψ’ to J/Ψ ratio (in m+m- channel) • Independent of and rapidity? E789 – 800 GeV p-Au PRD52, 1307 (1995) NA50 – 200 & 450 GeV p-A PLB 444, 516 (1998) Mike Leitch - LANL

  16. J/Ψ Polarization • NRQCD based predictions [Braaten & Fleming, PRL 74, 3327 (1995)] necessary to explain CDF charm cross sections • E866 measurement not in agreement with NRQCD based predictions [Beneke & Rothstein, PRD 54, 2005 (1996)] which give 0.31 < λ < 0.63 • or with color-singlet models [PRD 51, 3332 (1995)] • Complicated by feedown (~40%) from higher mass states. • No clear information on production mechanism! CDF E866/NuSea Mike Leitch - LANL

  17. Upsilon Polarization – E866/NuSea, Phys. Rev. Lett. 86, 2529 (2001) Υ2S+3S DY Y1S Y1S Υ2S+3S Υ2S+3S DY Y1S • Υ2S+3S has maximal polarization, • like Drell-Yan • Y1S has very small polarization Mike Leitch - LANL

  18. Summary: PRL 84, 3256 (2000) • 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 xF and pT that help reveal the underlying mechanisms Eskola, Kolhinen, Vogt hep-ph/0104124 • 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 Mike Leitch - LANL

  19. Summary continued – PT broadening: • A universal phenomena seen with, e.g. p, p and beams. • is ~5 times larger for J/Y than for Drell-Yan; cause? • gluons interact more strongly than quarks by 9/4 color factor • resonances can multiple scatter in final state • J/Y grows with • Radiative energy loss associated with Drell-Yan pT broadening in the BDMS model is tiny Mike Leitch - LANL

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