p(d)a physics in e866/nusea and phenix

Donald Isenhower - ACU

p(d)A Physics in E866/NuSea and PHENIX

Donald Isenhower - Abilene Christian [email protected]

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 physicsp(d)A physics in E866/NuSea & comparison to PHENIX pT broadening & polarizationPHENIX muon system complete for Run 3 - newsSummary


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

E866/NuSea


• Forward xF, 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


DY

Open CharmRandoms

E866/NuSea

Donald Isenhower - ACURatios of measured Drell-Yan pp and pd cross sections to NLO based on MRST2001

E866/NuSea

E866/NuSea

Donald Isenhower - ACUE866 Drell-yan cross sections per nucleon for selected xF bins

E866/NuSea


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


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


JHF Letter of IntentPhysics 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

Donald Isenhower - ACUE866/NuSea


FNAL E906pA 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


E906 comparison to NMC, E139, and E886

E866/NuSea


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/

cc

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

E866/NuSea


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/, ', • 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

E866/NuSea


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/ and ’ similar at large xF where they both correspond to a traversing the nucleus•but ’ absorbed more strongly than J/ 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

E866/NuSea


Correction to Nuclear Dependence for pT Acceptance

•Incomplete coverage in pT can distort J/ suppression versus xF

•E866/NuSea pT coverage is much better than previous experiment (e.g. E772) because of improved trigger•Most significant effects are at lowest xF where pT is cut off near 1 GeV/c•Use MC acceptance & /dpT consistent with our data to correct for incomplete coverage

E866/NuSea


• 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

PT broadening Summary

><Δ 2Tp

s

p

><Δ 2Tp

E866/NuSea


Gluon Shadowing for J/ ’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 µ

PHENIX eE866 (mid-rapidity)NA50

E866/NuSea


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 dataJ/

’

xF

R(A

u/

p)

yCM

yCM

’

J/

J/200 GeV p+Au

(RHIC)+dE/dx

w/o dE/dxp-Au at RHIC: Predictions•J/ & ’ differences at negative rapidity•Effect of dE/dx, also at negative rapidity

PHENIX Muon Arms

pre-resonance

fully-formedresonances

cc cc

E866/NuSea


Gluon shadowingGerland, Frankfurt, Strikman,

Stocker & Greiner (hep-ph/9812322)

Q = 2 GeV5 GeV

10 GeV

.74.4Kopeliovich…

.87.75w/o anti-shadowing

.84.66Eskola…

.921No shadowing difference

from fixed-target expt.

αR“Model”

50)/(

)/(

NA

PHENIX

HWR

HWRR −…

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


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 ~ Ks ~ 1 GeV/fm

•Multiple bremstrahlung:dE/dz ~ 3/ <kT

2> ~ .8 GeV/fm

•Radiative gluon (BDMS):ΔE ~ 3/8 Δ<pT

2><L> ~ .075 GeV/fm(since <pT

2> ~ 0.1 GeV2 from E772)

Total ΔE ~ 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

/2 JE

2// 22 = JJcoherence MEt

E866/NuSea


Kopeliovich, Tarasov, Hufnerhep-ph/0104256 E866 data

Full calculation

Model:• absorption•Dynamic calculation of shadowing and of energy loss•Also gluon anti-shadowing from Eskola

cc

E866/NuSea


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

• Y2S+3S has maximal polarization,like Drell-Yan•Y1S has very small polarization

Y1S

Y2S+3S

Y1S

Y2S+3SDY

DYY2S+3S

Y1S

E866/NuSea


Part 2: PHENIX J/ measurement with muon arms in d-Au

interactions at√ sNN = 200 GeV


The Collaboration

A strongly international venture:– 12 nations

Brazil, China, France, Germany, Hungary, India, Israel, Japan, South Korea, Russia, Sweden, United States

57 institutions


The PHENIX Detector • e, , h (Central Arms)

– || < 0.35, Δ = – pT > 0.2 GeV/c

(Muon Arms)– 1.2 < || < 2.4, Δ = 2– ptot > 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)


MagnetMagnetMuon IdentifiersMuon Identifiers

MuonMuon12.5°12.5°

35°35° 35°35°

10.5°10.5°

2 Muon Trackers = 2 Muon Trackers =

2x3 stations2x3 stations

2 Muon Identifiers 2 Muon Identifiers

= 2x5 planes= 2x5 planes

South Arm: South Arm: Began operationsin 2001-2002 run.

North Arm:North Arm:Installed in 2002.

Acceptance : 1.2 < || < 2.4

ΔMuon minimum momentum ~ 2 GeV/c

TrackingTrackingStationsStations

PHENIX Muon Arms


MUON IDENTIFIER

Small panel

Large panel

The South Muon Identifier


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


End view of Muon Tracker - South


Side view of PHENIX detectorNorth Muon Tracker is seen on the right partially exposed


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, ΔG(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~)


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 pT 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

GeV 200NNs


p+p J/X cross sections

µ+µ-

e+e-

Br (J/l+l-) (p+pJ/X)= 226 36 (stat.) 79 (syst.)

nb (p+pJ/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


Run-2 pp

Preliminary results: South MUTR radiograph:

Significant improvements in hardware and software and machine performance since then.


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


xF is defined as x

F = 2*p

z/sqrt(s).

With the help of = m2/s, we can obtain x

1 and x

2:

x1 = 1/2*(x

F+sqrt(x

F2+4*));

x2 = x

1 - x

F

At the large s value of RHIC, is small, as is therefore also x

2. The

x2 distributions are plotted for

simulated J/'s.

Kinematics

North Central South


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.


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)


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 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


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.

p(d)a physics in e866/nusea and phenix

Documents

measured drellyan pp

pd cross sections

e866nusea comparison

e866nusea disadvantages

pp collisions

pd collisions

preparation fnal e866nusea

pda results