2011 年 10 月 24 日 , GCOE コロキウム @ 東工大

Commissioning Status of the Drift Chamber for a Di-Muon Spectrometer at the E906/SeaQuest

Experiment at Fermilab

2011 年 10 月 24 日 , GCOE コロキウム @ 東工大

Florian Sanftl, 柴田研究室

2

Outline

1) Physics Motivation & Introduction2) E906/SeaQuest: Physics Goal3) Muon Pair Spectrometer4) Design and Commissioning of Drift Chamber built by

Japanese Group5) Track Reconstruction Algorithm / XT curve / position

resolution of charged particles6) Conclusion & Outlook

2011 年 10 月 24 日 GCOE コロキウム @ 東工大

3

Photon

e+

e-

1) Physics Introduction & Motivation

Proton Three “Valence” quarks 2 “up” quarks (q = +⅔) 1 “down” quark (q = -⅓)

Bound together by gluons Gluons can split into quark-

antiquark pairs (similar to the photon splitting into a electron-positron pair)

The Proton “Sea” is formed ofquarks and antiquarks

What is the Proton?

Gluons

Sea-quarks


4

Purpose of our Study

Is ū = đ valid in the Proton?

Is there a Flavor Asymmetry of Anti-quarks in the Proton?

đ - ū ≠ 0?

đ/ū ≠ 1?


5

How can we measure Sea-Quarks?


Deep Inelastic Scattering (DIS) Drell-Yan Process

Electron beam scatters off a proton Electromagnetic interaction

between electron and quark Comparing electron before and

after interaction reveals information about the proton structure

Proton beam scatters off a proton Quark and anti-quarks annihilate

into virtual photon Virtual photon decays into two

muons Anti-quarks can be selected

Proton / Target

Proton / Beam

Proton

90° Rotation

6

Importance of ‘Bjorken-x’ xB and Q2


Q2:4-momentum transferred squared (“virtuality of photon”)Q2 = -q2 = 2EeE’e(1+cosθl)

Alternative way for Q2:Q2 also represents spatial resolution where proton is probedr = hc/Q = 0.2fm/Q[GeV]typically Q2 > 1GeV2, r < 0.2*10-15 m

Bjorken-x:xB = fractional momentum carried by the struck quarkxB = pQUARK / pPROTON

0 ≤ xB ≤ 1 q(xB,Q2):

probability to hit a quark with flavour q, xB and Q2

7

Experimental Results

2011 年 10 月 24 日

Unknown effects

apparently dilutes meson cloud effects

at large-x

NMC (Gottfried Sum Rule)

NA51 (Drell-Yan)

E866/NuSea (Drell-Yan)

ū ≠ đ

đ - ū đ / ū

GCOE コロキウム @ 東工大

8

2) The E906/SeaQuest Experiment


Old Experiment:Fermilab E866/NuSea

1H, 2H, and nuclear targets 800 GeV proton beam

New Experiment:Fermilab E906/SeaQuest

1H, 2H, and nuclear targets 120 GeV proton Beam

Higher Cross section and Less Background

50x statistics!!Fixed Target

Beam lines

Tevatron 800 GeV

Main Injector 120 GeV

9

Physics Goal


E906/Drell-Yan will extend old measurements toxB values > 0.3 and reduce statistical uncertainty.

25m

Solid Iron

Focusing Magnet,

Hadron absorber

and beam dump

4.9m

Mom. Meas.

(KTeV Magnet)

Hadron Absorber

(Iron Wall)

Station 1:

Hodoscope array

MWPC tracking

Station 4:

Hodoscope array

Prop tube tracking

Liquid H2, d2, and

solid targets

Station 2 and 3:

Hodoscope array

Drift Chamber tracking

Drawing: T. O’Connor and K. Bailey

Station 3: NEW from Tokyo Tech

2011 年 10 月 24 日 GCOE コロキウム @ 東工大 10

3) Muon Pair Spectrometer

• St. 4 Prop Tubes: Homeland Security via Los Alamos• St. 3 & 4 Hodo PMT’s: E-866, HERMES, KTeV• St. 1 & 2 Hodoscopes: HERMES• St. 2 & 3Minus- tracking: E-866• St. 3: NEW from Japanese Collaborators• St. 2 Support Structure: KTeV• Target Flasks: E-866• Cables: KTeV

• 2nd Magnet: KTeV Analysis Magnet• Hadron Absorber: Fermilab Rail Head???

• Solid Fe Magnet Coils: E-866 SM3 Magnet• Shielding blocks: old beamline (Fermilab Today)

• Solid Fe Magnet Flux Return Iron: E-866 SM12 Magnet

Expect to start collecting data this autumn!


Motivation: Re-do, Re-use & Re-cylce

http://www.fnal.gov/pub/today/archive_2010/today10-09-24.html

12

Spectrometer Top View


25 m

μ+

U U’V

XV’

X’

Cell Structure• Cell width & height 20 mm• Wire spacing 10 mm• Diameter sense wire (Au-W) 30 μm,

others (Au-CuBe) 80 μmPerformance Parameters• Gas-gain ~4.0E5• Drift velocity 3-6 cm / μsec (Ar:CO2)


General Performance requirements• Detection Area:

1.6 m (vertical) x 2.2 m (horizontal)• 6 Active layers:

U/U’ (+14°), X/X’ (0°), V/V’ (-14°)• Position resolution: < 400 μm per planeGas Selection:• For now: Argon:CO2 (80:20)

4) Design of the New Drift Chamberμ+ / μ-

14

June, 2009

January, 2010

March, 2010

July, 2010

Now

STATUS of Station 3+ DC

Tests at RIKEN

Tests at Fermilab

Installation & Setup in

Spectrometer

Design completed

Fabrication completed

Transport to RIKEN

Transport to Fermilab


Commissioning Timeline

Measure time difference between trigger and Signal

from Chamber

Convert time to distance by

simulation(GARFIELD)

ReconstructTrack

(5 layer based)

2-dim distribution

Time vs. Distance

Project distance distributions and fit

for position resolution

Extract new time to distance relation

We are measuring:• Coincidence between

bottom and top scintillator caused by cosmic rays

• Time difference between coincidence and signal from chamber

Accepted Hits

Projected distance


5) Track Reconstruction AlgorithmReconstructed track

Scintillator

Iteration

ScintillatorCosmic Ray

XT extraction:• 1st Iteration• Extracted curve agrees well with input

curve within uncertainties• Still too little statistics from the edge of

cell


Deviation simulation between measurement:• Green bands is width of the projections• Those are constant over a wide T range• Band corresponds to position resolution

of 500μm• Tilting behavior due to statistical effects

Results and Discussion


• E906/SeaQuest is a Drell-Yan experiment• It measures the asymmetry of anti-quarks in the proton• Tokyo Tech group designed and built and a new drift chamber• We prepared a Track Reconstruction Algorithm• Algorithm is working well• We already achieved a position resolution of 500μm which is very

close to the design value of 400μm• Improvement by more iterations• We are ready for the first beam in November 2011!!!

6) Conclusion and Outlook

18

The E906 Collaboration


Abilene Christian UniversityObiageli AkinbuleBrandon BowenMandi CrowderTyler HagueDonald IsenhowerBen MillerRusty TowellMarissa WalkerShon WatsonRyan Wright

Academia SinicaWen-Chen ChangYen-Chu ChenShiu Shiuan-HalDa-Shung Su

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

University of ColoradoJoshua BravermanEd KinneyPo-Ju LinColin West

Fermi National Accelerator LaboratoryChuck BrownDavid Christian

University of IllinoisBryan DannowitzDan JumperBryan KernsNaomi C.R MakinsJen-Chieh Peng

KEKShin'ya Sawada

Ling-Tung UniversityTing-Hua Chang

Los Alamos National LaboratoryGerry GarveyMike LeitchHan LiuMing Xiong LiuPat McGaughey

University of MarylandPrabin AdhikariBetsy BeiseKaz Nakahara

University of MichiganBrian BallWolfgang LorenzonRichard Raymond

National Kaohsiung Normal UniversityRurngsheng GuoSu-Yin Wang

RIKENYuji GotoAtsushi TaketaniYoshinori FukaoManabu Togawa

Rutgers UniversityLamiaa El FassiRon GilmanRon RansomeElaine SchulteBrian TiceRyan ThorpeYawei Zhang

Texas A & M UniversityCarl GagliardiRobert Tribble

Thomas Jefferson National Accelerator FacilityDave GaskellPatricia Solvignon

Tokyo Institute of TechnologyToshi-Aki ShibataKenichi Nakano

Florian SanftlShintaro TakeuchiShou Miyasaka

Yamagata UniversityYoshiyuki Miyachi

19

Flavor Asymmetry: Models


LA-LP-

98-56

Chiral Quark models—effective Lagrangians

Meson Cloud in the nucleon—Sullivan process in DIS

Instantons

Statistical Parton Distributions

Antiquarks in spin 0 object → No net spin

Pauli Blocking:Excess of up-quarks permits creation of up-anti-up-pairs

Documents

2011 年 10 月 24 日 , GCOE コロキウム @ 東工大