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 東工大 Florian Sanftl, 柴田研究室

Outline 2 1)Physics Motivation & Introduction 2)E906/SeaQuest: Physics Goal 3)Muon Pair Spectrometer 4)Design and Commissioning of Drift Chamber built by Japanese Group 5)Track Reconstruction Algorithm / XT curve / position resolution of charged particles 6)Conclusion & Outlook 2011 年 10 月 24 日 GCOE 東工大

Photon e+ e- 1) Physics Introduction & Motivation 3 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 of quarks and antiquarks What is the Proton? Gluons Sea-quarks 2011 年 10 月 24 日 GCOE 東工大

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? 年 10 月 24 日 GCOE 東工大

How can we measure Sea-Quarks? 年 10 月 24 日 GCOE 東工大 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

Importance of ‘Bjorken-x’ x B and Q 年 10 月 24 日 GCOE 東工大  Q 2 : 4-momentum transferred squared (“virtuality of photon”) Q 2 = -q 2 = 2E e E’ e (1+cosθ l )  Alternative way for Q 2 : Q 2 also represents spatial resolution where proton is probed r = hc/Q = 0.2fm/Q[GeV] typically Q 2 > 1GeV 2, r < 0.2* m  Bjorken-x: x B = fractional momentum carried by the struck quark x B = p QUARK / p PROTON  0 ≤ x B ≤ 1  q(x B,Q 2 ): probability to hit a quark with flavour q, x B and Q 2

Experimental Results 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 東工大

2) The E906/SeaQuest Experiment 年 10 月 24 日 GCOE 東工大 Old Experiment: Fermilab E866/NuSea  1 H, 2 H, and nuclear targets  800 GeV proton beam New Experiment: Fermilab E906/SeaQuest  1 H, 2 H, and nuclear targets  120 GeV proton Beam  Higher Cross section and  Less Background 50x statistics!! 50x statistics!! Fixed Target Beam lines Tevatron 800 GeV Main Injector 120 GeV

Physics Goal 年 10 月 24 日 GCOE 東工大 E906/Drell-Yan will extend old measurements to x B values > 0.3 and reduce statistical uncertainty.

25m Solid Iron 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 H 2, d 2, 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 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 2 nd Magnet: KTeV Analysis Magnet Hadron Absorber: Fermilab Rail Head??? Solid Fe Magnet Coils: E-866 SM3 Magnet Shielding blocks: old beamline (Fermilab Today)Fermilab Today Solid Fe Magnet Flux Return Iron: E-866 SM12 Magnet Expect to start collecting data this autumn! 2011 年 10 月 24 日 GCOE 東工大 11 Motivation: Re-do, Re-use & Re-cylce

Spectrometer Top View 年 10 月 24 日 GCOE 東工大 25 m μ+μ+

U U’ V X V’ X’ Cell Structure Cell width & height 20 mm Wire spacing 10 mm Diameter sense wire (Au-W) 30 μm, others (Au-CuBe) 80 μm Performance Parameters Gas-gain ~4.0E5 Drift velocity 3-6 cm / μsec (Ar:CO 2 ) 2011 年 10 月 24 日 GCOE 東工大 13 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 plane Gas Selection: For now: Argon:CO 2 (80:20) 4) Design of the New Drift Chamber μ + / 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 2011 年 10 月 24 日 GCOE 東工大 Commissioning Timeline

Measure time difference between trigger and Signal from Chamber Convert time to distance by simulation(GARFIELD) Reconstruct Track (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 2011 年 10 月 24 日 GCOE 東工大 15 5) Track Reconstruction Algorithm Reconstructed track Scintillator Iteration Scintillator Cosmic Ray

XT extraction: 1 st Iteration Extracted curve agrees well with input curve within uncertainties Still too little statistics from the edge of cell 2011 年 10 月 24 日 GCOE 東工大 16 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

2011 年 10 月 24 日 GCOE 東工大 17 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

The E906 Collaboration 年 10 月 24 日 GCOE 東工大 Abilene Christian University Obiageli Akinbule Brandon Bowen Mandi Crowder Tyler Hague Donald Isenhower Ben Miller Rusty Towell Marissa Walker Shon Watson Ryan Wright Academia Sinica Wen-Chen Chang Yen-Chu Chen Shiu Shiuan-Hal Da-Shung Su Argonne National Laboratory John Arrington Don Geesaman* Kawtar Hafidi Roy Holt Harold Jackson David Potterveld Paul E. Reimer* Josh Rubin University of Colorado Joshua Braverman Ed Kinney Po-Ju Lin Colin West Fermi National Accelerator Laboratory Chuck Brown David Christian University of Illinois Bryan Dannowitz Dan Jumper Bryan Kerns Naomi C.R Makins Jen-Chieh Peng KEK Shin'ya Sawada Ling-Tung University Ting-Hua Chang Los Alamos National Laboratory Gerry Garvey Mike Leitch Han Liu Ming Xiong Liu Pat McGaughey University of Maryland Prabin Adhikari Betsy Beise Kaz Nakahara University of Michigan Brian Ball Wolfgang Lorenzon Richard Raymond National Kaohsiung Normal University Rurngsheng Guo Su-Yin Wang RIKEN Yuji Goto Atsushi Taketani Yoshinori Fukao Manabu Togawa Rutgers University Lamiaa El Fassi Ron Gilman Ron Ransome Elaine Schulte Brian Tice Ryan Thorpe Yawei Zhang Texas A & M University Carl Gagliardi Robert Tribble Thomas Jefferson National Accelerator Facility Dave Gaskell Patricia Solvignon Tokyo Institute of Technology Toshi-Aki Shibata Kenichi Nakano Florian Sanftl Shintaro Takeuchi Shou Miyasaka Yamagata University Yoshiyuki Miyachi

Flavor Asymmetry: Models 年 10 月 24 日 GCOE 東工大 LA- LP  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