Charming Measurements in E866/NuSea

Mike Leitch - LANL1

Charming Measurements in E866/NuSea

Mike Leitch - Los Alamos National [email protected]

Charm Production: from Threshold via SPS to RHIC and LHC

European Center for Theory, June 17-22, 2002

Introduction to Physics of Drell-Yan & Charmonium suppression in nucleiE866/NuSea & comparison to NA50 pT broadening & polarizationSummary

E772 - 1991

Mike Leitch - LANL2

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 effectsProduction 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

Nuclear modification of parton level structure & dynamics

bb)(2 2

/2

'/ JJH mmEl2

//2 JJC mEl

cc

Drell-Yan

E866 R(W/Be)E772 R(W/D)

Rat

io(W

/Be) 1.0

0.9

0.8

0.7

NMC DIS

Drell-Yan Process

Mike Leitch - LANL3

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

DY

J/

cc

Peng et al, PLB 344 (1995) 1-5.

Mike Leitch - LANL4

FNAL E866/NuSea CollaborationAbilene Christian University

Donald Isenhower, Mike Sadler, Rusty Towell, Josh WillisArgonne National Laboratory

Don Geesaman, Sheldon Kaufman, Bryon MuellerFermi National Accelerator Laboratory

Chuck Brown, Bill CooperGeorgia State University

Gus Petitt, Xiao-chun He, Bill LeeIllinois Institute of Technology

Dan KaplanLos Alamos National Laboratory

Tom Carey, Gerry Garvey, Mike Leitch, Pat McGaughey,Joel Moss, Jen-Chieh Peng, Paul Reimer, Walt Sondheim

New Mexico State UniversityMike Beddo, Ting Chang, Vassili Papavassiliou, Jason Webb

Oak Ridge National LaboratoryPaul Stankus, Glenn Young

Texas A & M UniversityCarl Gagliardi, Bob Tribble, Eric Hawker, Maxim Vasiliev

Valparaiso UniversityDon Koetke

Mike Leitch - LANL5

• 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

FNAL E866/NuSea

Mike Leitch - LANL6

Scaling of J/ Suppression?•Comparison of 800 GeV (E866) and 200 GeV (NA3) -appears to scale only with xF

E866/NuSea: 800 GeV p-A (Fermilab)PRL 84, 3256 (2000)

• 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.

cc

open charm: no A-depat mid-rapidity

HadronizedJ/

cc

Mike Leitch - LANL7

PT Broadening at 800 GeV

(pT) shape is independent of xF & same for NA3 at a lower energy(curves are with A slightly different for each)

)011.06.1()( 2TTT ppAp

E772 & E866: p-A at 800 GeV

Drell-Yan

J/ & ’

Upsilons

Mike Leitch - LANL8

Comparison to NA50 J/Ψ Nuclear Dependence

Expt. E(GeV) YCM J/Ψ J/Ψ - Ψ

E866 800 -0.4 to 1.0 .954 ± .001 .027 ± .006*

NA50 450 -0.4 to 0.6 .925 ± .018 .029 ± .014

NA38 200 0 to 1.0 .911 ± .034

-0.4 1.0yCM :

* mid-rapidity part of E866 data

y~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)

Charmonia cross sections from NA50/51 for p-A collisions at 450 GeV/c

NA50/51450 GeV

E866800 GeV

p-p & p-d

’

J/

s

s

Mike Leitch - LANL9

J/Deuterium/Hydrogen Ratios

A = 1.35A = 1.2

A = 2A = 2

)011.06.1()( 2TTT ppAp )034.052.1()( 2

FFF xxAx Using fits to E866/NuSea p + Be, Fe, W data:

Preliminary

Preliminary

Mike Leitch - LANL10

Gluon Shadowing for J/Ψ’s

Kopeliovich, Tarasov, & Hufnerhep-ph/0104256

Eskola, Kolhinen, Vogt hep-ph/0104124J.C.Peng, LANL

E866/NuSeaPHENIXμ+μ- 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 μPHENIX eE866 (mid-rapidity)NA50


PT Broadening for different energies and probes – other data

NA10 140,286 GeV - DYPLB 193, 368 (1987)E288 400 GeV p DY

PRD 23, 604 (1981)

Antipov, 43 GeV - J/PL76B, 235 (1978)

E537 125 GeV p,- J/PRL 60, 2121 (1988)

Omega 39.5 GeV - J/PL110B, 415 (1982)


Systematics of PT Broadening


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

Proton Pion

χ,1,2 J/Ψ 30% 37%

Ψ΄ J/Ψ 5.5% 7.6%

Meson M(GeV) R(Fm)BE

(MeV)

J/Ψ 3.1 .45 ~640

Ψ΄ 3.7 .88 ~52

χC 3.5 .70


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 -

WA78 320 GeV -

(Beam dump)

E789 : PRL 72, 2542 (1994)800 GeV p + A, <xF> = 0.03 = 1.02±.03±.02


Ψ’ to J/Ψ ratio (in +- channel)

E789 – 800 GeV p-AuPRD52, 1307 (1995)

NA50 – 200 & 450 GeV p-APLB 444, 516 (1998)

•Independent of and rapidity?s


J/Ψ Polarization

E866/NuSea

CDF

)cos1(cos/ 2 Add

)cos1(cos/ 2 Add

•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!


Upsilon Polarization – E866/NuSea, Phys. Rev. Lett. 86, 2529 (2001)

• Υ2S+3S has maximal polarization,like Drell-Yan•Y1S has very small polarization

Y1S

Υ2S+3S

Y1S

Υ2S+3SDY

DYΥ2S+3S

Y1S


Summary:

•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

•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

cc

Eskola, Kolhinen, Vogt hep-ph/0104124

PRL 84, 3256 (2000)


• 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 pT broadening in the BDMS model is tiny

Summary continued – PT broadening:

2Tp

s

p

2Tp

Charming Measurements in E866/NuSea

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