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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