E906/SeaQuestDrell-Yan Experiment

Kazutaka NakaharaUniversity of Maryland College Park

for the E906 Collaboration

June 8th, RHIC/AGS User’s Meeting

Nucleon Structure • Light sea quark• Gottfried Sum Rule:

SG = 1/3 if u = d

[ ]

[ ]

31

32

31 1

0

1

022

=

−+=

−=

∫

∫

dxdu

xdxFFS np

G Charge Symmetry

du =

NMC Measurement

SG = 0.235 +/- 0.026

New Muon Collaboration (NMC), Phys. Rev. D50 (1994) R1

Extrapolate results over all x (0 < x < 1)

0.004 < x < 0.8

Nuclear shadowing (double scattering of virtual photon from both nucleons in deuteron) ~ 4-10% effect on Gottfried sum disagreement with naive calculation of GSR remains

Reconciling the DisconnectThree assumptions:NMC:1. Extrapolation of NMC measurement to

lower x?

GSR:1. Charge symmetry?

2. ?du =

E665 experiment measured to lower x

No signs of charge symmetry breaking

Directly measure through Drell-YanKnowledge is data-driven

First Direct Measurement

• NA51 (Drell-Yan) shows u < dTarget

Beam x1, q

x2, qγ*

µ+

µ-

( )( )

( )( )

+≈

+

+

+

≈>>

)()(1

21

)()(1

)()(

411

411

21

2

2

2

2

2

2

2

1

1

1

1

|21

xuxd

xuxd

xuxd

xuxd

xuxd

xxpp

pd

σσ

E866 Drell-Yan

Target

Beam x1, q

x2, qγ*

µ+

µ-

( )( )

( )( )

+≈

+

+

+

≈>>

)()(1

21

)()(1

)()(

411

411

21

2

2

2

2

2

2

2

1

1

1

1

|21

xuxd

xuxd

xuxd

xuxd

xuxd

xxpp

pd

σσ

E866 Drell-Yan• Fermilab Meson East Building• 800 GeV proton beam• 0.04 < x < 0.35• Uncertainties dominated by

statistics (~1% systematic uncertainties in cross section ratio)

( )( )

( )( )

+≈

+

+

+

≈>>

)()(1

21

)()(1

)()(

411

411

21

2

2

2

2

2

2

2

1

1

1

1

|21

xuxd

xuxd

xuxd

xuxd

xuxd

xxpp

pd

σσ

Tevatron 800 GeV

Main Injector 120 GeV

E-906/SeaQuest CollaborationAbilene Christian University

Obiageli AkinbuleBrandon BowenMandi CrowderTyler HagueDonald IsenhowerBen MillerRusty TowellMarissa WalkerShon WatsonRyan Wright

Academia Sinica

Wen-Chen ChangYen-Chu ChenShiu Shiuan-HalDa-Shung Su

Argonne National LaboratoryJohn ArringtonDon Geesaman*Kawtar HafidiRoy HoltHarold JacksonDavid PotterveldPaul E. Reimer*Josh Rubin

University of Colorado

Joshua BravermanEd KinneyPo-Ju LinColin West

Fermi National Accelerator Laboratory

Chuck BrownDavid Christian

University of Illinois

Bryan DannowitzDan JumperBryan KernsNaomi C.R MakinsJen-Chieh Peng

KEK

Shin'ya Sawada

Kyoto University

KenIchi ImaiTomo Nagae

Ling-Tung University

Ting-Hua Chang

Los Alamos National Laboratory

Gerry GarveyMike LeitchHan LiuMing Xiong LiuPat McGaughey

University of MarylandBetsy BeiseKaz Nakahara

University of MichiganChiranjib Dutta

Wolfgang LorenzonRichard Raymond

National Kaohsiung Normal University

Rurngsheng GuoSu-Yin Wang

University of New Mexico

Imran Younus

RIKEN

Yuji GotoAtsushi TaketaniYoshinori FukaoManabu Togawa

Rutgers University

Lamiaa El FassiRon GilmanRon RansomeElaine SchulteBrian TiceRyan ThorpeYawei Zhang

Texas A & M University

Carl GagliardiRobert Tribble

Thomas Jefferson National Accelerator Facility

Dave GaskellPatricia Solvignon

Tokyo Institute of Technology

Toshi-Aki Shibata

Ken-ichi Nakano

Yamagata University

Yoshiyuki Miyachi

*Co-Spokespersons

E906 Drell-Yan• 120 GeV proton beam

(E866: 800 GeV)– cross section scales as 1/s:

7x statistics

– background scales as s:

7x luminosity

50x statistics

• Systematic uncertainties ~1%

What happens at high x?

Other Physics to be Probed with Drell-YanPartonic energy loss in nuclei• Beam quark lose energy as it penetrates nucleus

shift in observed parton momentum fractionmeasure energy loss by using different size nuclei establish a baseline for energy loss expected in heavy

ion collision

Drell-Yan Spectrometer for E-906

Had

ron

Abs

orbe

r

Liquid H2, d2, and solid targets

• Statistics are better, but some issues to keep in mind:• Lower particle energy increased muonic decay of hadronicbackground• Lower energy muons multiple scatter more readily in the hadronabsorber

Magnet Installation

• Focusing magnet (FMAG) installed• Momentum measuring magnet (KMAG) installed• Hadron absorber• Beam dump (watch muons from J/ψ)

E906 Beam• 53 MHz beam repetition frequency (18.9ns)• 5 seconds every minute: 2 ×1012 protons/sec

(4 kW beam, 5 W deposited on target,1 ×1013 protons/min)• at least 5.2 ×1018 total protons for experiment

5 seconds

6 trains of 81 RF buckets

18.9 ns RF buckets

. . .

E906 Target• 2 liter LH2 and LD2 target flasks• Empty target for target systematics• Solid targets (C, W, Ca, ??)• Targets on movable table: change

targets between pulses (each min)• Closed circuit GM cryocoolers cools a

condenser• H2/D2 liquifies in condenser drips

(fills) into target flask

Detectors• Station 1: MWPC (Multi-Wire Proportional Chamber)• Station 2: E866 Station 2• Station 3: Two halves

– Lower half: E866 Drift Chamber– Upper half: Newly designed and constructed

• Station 4: Muon Prop. Tubes• Hodoscope scintillators to trigger info. For all four stations

Schedule• First commissioning beam in July (?) 2010 depending on

machine schedule.• Experiment with H2/D2 to begin late 2010.• Run with full beam ~2 years• Prospects for further Drell-Yan experiments at J-PARC (50

GeV) or Fermilab Main Injector (60 GeV)

2009

2008

2011

Publications

Expt. Funded

2010Magnet Design ExperimentAnd construction Construction

Prop

osed

Jan.

200

7

ExperimentRuns

J-PARC

2012

• E906 experiment will extend the measurement of light anti-quark asymmetries– to higher x– with greater statistics

• Absolute pp, pd cross sections• Partonic energy loss• Structure of nucleonic matter• Commissioning to start in July• Data-taking to start late 2010

20

Is in the proton?

Gottfried Sum Rule 1

2 20

1

0

[( ( ) ( )) / ]

1 2 ( ( ) ( ))3 3

( )13 p p

p nG

p p

S F x F x x dx

u x d

i

x dx

f u d

= −

= −

= =

+

∫

∫

=du =

21

Drell-Yan fixed target experiments at Fermilab• What is the structure of the

nucleon?➡ What is ?➡ What is the origin of the

sea quarks?➡ What is the high x

structure of the proton?

• What is the structure of nucleonic matter?➡ Where are the nuclear pions?➡ Is anti-shadowing a valence effect?

• Do colored partons lose energy in cold nuclear matter?

/d u

• SeaQuest: 2010 - 2012➡ significant increase in physics reach

• Beyond SeaQuest➡ Polarized Drell-Yan➡ Pionic Drell-Yan

• EMC effect parton distributions of bound vs free nucleons

• What can the sea parton distributions tell us about nuclear binding?

• E906: Measure nuclear effects precisely

Other Physics to be Probed with Drell-Yan