Drell-Yan実験 - Fermilab-E906/SeaQuest実験 - 偏極Drell-Yan実験の計画 放射線研PHENIXミーティング 2011年1月21日(金) 後藤雄二

Fermilab-E906/SeaQuest実験 Drell-Yan過程からのdimuonの測定 物理ランは今春開始 物理の結果はまだない 建設と設置が進行中 3月からビームを用いた調整 Fixed Target Beam lines Tevatron 800 GeV Main Injector 120 GeV January 21, 2011

実験の目標 Drell-Yan過程 核子構造 核物質 ハドロン同士の反応において最も単純な過程 ターゲットのsea-quark分布を選択 QCD終状態効果がない ターゲットのsea-quark分布を選択 核子構造 水素および重水素標的 Sea-quark分布のフレーバー非対称性 Boer-Mulders分布関数 核子スピン構造との関連 核物質 原子核標的 パートンのエネルギー損失 EMC効果 January 21, 2011

Sea-quark分布のフレーバー非対称性 Fermilab E866/NuSea Sea-quark分布のフレーバー非対称性 Ebeam = 800 GeV x = 0.01 – 0.35 (valence region) Fermilab E906/SeaQuest Ebeam = 120 GeV x = 0.1 – 0.45 競合する説明 摂動論的QCD グルーオンの解離 非摂動論的QCDからの寄与 中間子雲模型 カイラルクォーク模型 January 21, 2011 4

EMC効果 1983年、EMC (European Muon Collaboration) がミューオンDIS実験において発見 原子核中のパートン分布が核子中の分布に対して修正を受ける 仮想中間子の交換が原子核中のパートン分布に修正を与える 現在あるDrell-Yan過程のデータには、この修正がないことが示唆される Shadowing Anti-Shadowing EMC Effect January 21, 2011

Fermilab E906/SeaQuest Collaboration 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 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 Ken-ichi Nakano Florian Sanftl S. Miyasaka S. Takeuchi Yamagata University Yoshiyuki Miyachi *Co-Spokespersons January 21, 2011

スケジュール http://www.fnal.gov/directorate/program_planning/schedule/ January 21, 2011

Fermilab E906/SeaQuest timeline 2001年: Fermilab PACにより採択 2007年: DOE nuclear physicsから資金を得る 2008年-2009年: Fermilab所長によるステージ２採択およびFermilabとE906 collaborationの間でMoU (Memorandum of Understanding)が交わされる 2009年-2010年: 実験装置の建設および設置 2011年3月: ビームを用いた実験調整開始 2011年-2013年: 物理データ集積 2009 2008 2011 Publications Expt. Funded 2010 Magnet Design Experiment and Construction Construction Proposed Jan. 2007 Experiment Runs 2012 January 21, 2011

Dimuon spectrometer KMAG FMAG Momentum analysis Focusing magnet Hadron absorber Beam dump Momentum analysis FMAG KMAG January 21, 2011

NM4 hall (ex KTeV hall) & magnets FMAG KMAG January 21, 2011

水素/重水素標的 Cryocooler compressor Cryocooler coolhead Condenser Vacuum vessel Target test flask January 21, 2011

Station 3 ドリフトチェンバー 日本で建設 航空便で日本からFermilabへ輸送 2010.7.2 RIKEN January 21, 2011

飛跡検出器、エレキ Station 4 proportional tubes Hodoscopes for dimuon trigger Latch /TDC ASDQ card PAD card Readout electronics January 21, 2011

ここまでのまとめ Fermilab-E906/SeaQuest実験 立ち上げの現状 Drell-Yan過程からのdimuon測定 核子構造 Sea-quark分布のフレーバー非対称性 Boer-Mulders分布関数 核物質 EMC効果 パートンのエネルギー損失 立ち上げの現状 建設と設置が進行中 ビームライン、電磁石、飛跡検出器、ガス、エレキ、トリガー、ＤＡＱ Station 3 ドリフトチェンバーを日本で建設、2010年7月に航空便でFermilabへ輸送 2011年3月からビームを用いた調整 ビームの理解、検出器ゲイン・タイミング、トリガータイミング・レート・マトリクス、位置合わせ、ＤＡＱ、データ解析 今春物理データ収集を開始、2013年まで2年間集積 January 21, 2011

Introduction Transverse-spin asymmetry measurement Theoretical development to understand the transverse structure of the nucleon Sivers effect, Collins effect, higher-twist effect, … Relation to orbital angular momentum inside the nucleon FNAL-E704 s = 20 GeV RHIC-STAR s = 200 GeV There are measurement of the transverse-spin asymmetries. Large asymmetries in the forward region were shown in FNAL-E704 experiment, and also at RHIC, though the energy scale is 10-times different. In order to explain these and many other transverse-spin asymmetry data, there have been many theoretical developments to understand the transverse structure of the nucleon, for instance by Sivers effect, Collins effect, and higher-twist effect, and these are expected to have relation to orbital angular momentum inside the nucleon. January 21, 2011 15

Introduction Transverse structure of the proton Transversity distribution function Correlation between nucleon transverse spin and parton transverse spin TMD distribution functions Sivers function Correlation between nucleon transverse spin and parton transverse momentum (kT) Boer-Mulders function Correlation between parton transverse spin and parton transverse momentum (kT) To investigate the transverse structure of the proton, one important extension of the parton distribution function is a transverse-momentum dependent (TMD) distribution functions shown in this table. Three important functions are transversity distribution functions, Sivers function, and Boer-Mulders function. These are shown in the table of leading-twist transverse-momentum dependent distribution functions. The transversity distribution shows …, Sivers function shows …, and Boer-Mulders function shows …. Leading-twist transverse momentum dependent (TMD) distribution functions January 21, 2011 16

Sivers function Single-spin asymmetry (SSA) measurement M. Anselmino, et al. EPJA 39, 89 (2009) Single-spin asymmetry (SSA) measurement < 1% level multi-points measurements have been done for SSA of DIS process Valence quark region: x = 0.005 – 0.3 (more sensitive in lower-x region) Sivers function u-quark d-quark Because one of the most important goal of the experiment is the measurement and determination of the Sivers function, I show one more slide for the Sivers function. It is measured and determined by the single-spin asymmetry measurement. In the DIS, or deep-inelastic scattering experiment, it has already been measured less than 1% level multi-point measurement whose x-region x = 0.005 to 0.3 covers the valence quark region around x around 0.2. These are HERMES result and COMPASS result of the SSA measurement of semi-inclusive DIS with pi0, pi+ and pi- measurement. Using these data, this is the global-fitting result of the Sivers function of u-quark and d-quark by Anselmino’s group. January 21, 2011 17

Single transverse-spin asymmetry Sivers function Correlation between nucleon transverse spin and parton transverse momentum (Sivers distribution function) Related to the orbital angular momentum in the proton (and the shape of the proton) “Non-universality” of Sivers function Sign of Sivers function determined by SSA measurement of DIS and Drell-Yan processes should be opposite each other final-state interaction with remnant partons in DIS process Initial-state interaction with remnant partons in Drell-Yan process Fundamental QCD prediction One of the next milestones for the field of hadron physics Our important goal is a measurement of the Sivers function, which describe “correlation between …” and related to the orbital angular momentum The reason of the importance is its “non-universality” which has already discussed by many speakers in this workshop. “Sign of Sivers function …” because there is final-state interaction with remnant partons in DIS process, and there is initial-state interaction with remnant partons in Drell-Yan process. This is a fundamental QCD prediction, and one of the next milestones for the field of hadron physics. January 21, 2011 18

Future polarized Drell-Yan experiments particles energy x1 or x2 luminosity COMPASS + p 160 GeV s = 17.4 GeV x2 = 0.2 – 0.3 2 × 1033 cm-2s-1 (low mass) x2 ~ 0.05 PAX p + pbar collider s = 14 GeV x1 = 0.1 – 0.9 2 × 1030 cm-2s-1 PANDA pbar + p 15 GeV s = 5.5 GeV x2 = 0.2 – 0.4 2 × 1032 cm-2s-1 J-PARC p + p 50 GeV s = 10 GeV x1 = 0.5 – 0.9 1035 cm-2s-1 NICA s = 20 GeV x1 = 0.1 – 0.8 1030 cm-2s-1 RHIC PHENIX Muon s = 500 GeV x1 = 0.05 – 0.1 RHIC Internal Target phase-1 250 GeV s = 22 GeV x1 = 0.2 – 0.5 Target phase-2 3 × 1034 cm-2s-1 This is a table of proposed polarized Drell-Yan experiments in the world. In Europe, there are plans at COMPASS and GSI/FAIR. At COMPASS, it is a pion-induced experiment, and at GSI/FAIR, it is proton + antiproton experiments. In my talk, I will discuss plans at RHIC and J-PARC. Both are proton + proton Drell-Yan experiments. January 21, 2011 19

Polarized Drell-Yan experiments at RHIC “Transverse-Spin Drell-Yan Physics at RHIC” http://spin.riken.bnl.gov/rsc/write-up/dy_final.pdf Les Bland, et al., May 1, 2007 s = 200 GeV PHENIX muon arm STAR FMS (Forward Muon Spectrometer) Discussions at PHENIX and STAR underway in their decadal plan discussion with their upgrade plan Two new Letter-of-Intent submitted to BNL PAC Collider experiment dedicated to the polarized Drell-Yan experiment “Feasibility Test of Large Rapidity Drell-Yan Production at RHIC” Fixed-target experiment “Measurement of Dimuons from Drell-Yan Process with Polarized Proton Beams and an Internal Target at RHIC” For the polarized Drell-Yan experiements, there was one proposal made in 2007 by Les Bland, et al. which showed sensitivity with 200 GeV collisions with existing PHENIX muon arm and STAR FMS. The figure shows the sensitivity of both PHENIX and STAR compared with theory calculation. Recently discussions at PHENIX and STAR are underway in their decadal plan discussion with their upgrade plan. In addition to these, there are two new letter-of-intent submitted to BNL PAC this year. One is a collider experiment… Another is a fixed target expriment… January 21, 2011 20

Collider experiment LoI http://www.bnl.gov/npp/docs/pac0610/Crawford_LoI.100524.v1.pdf I just show two pages from the collider experiment LoI whose title is “Feasibility Test of Large Rapidity Drell-Yan Production at RHIC”. They want to start with a test experiment. This is the first page which show the authors from institutes from USA and Russia. January 21, 2011 21

Collider experiment LoI And this is their proposed final form of the experiment which identifies e+e- pair from the polarized proton-proton collision at here, interaction point. Detector consists of magnets, fiber trackers, MWPC, and EM & Hadron calorimeters. January 21, 2011 22

Fixed-target experiment LoI Measurement of Dimuons from Drell-Yan Process with Polarized Proton Beams and an Internal Target at RHIC http://www.bnl.gov/npp/docs/pac0610/Goto_rhic-drell-yan.pdf Academia Sinica (Taiwan): W.C. Chang ANL (USA): D.F. Geesaman, P.E. Reimer, J. Rubin UC Riverside (USA): K.N. Barish UIUC (USA): M. Groose Perdekamp, J.-C. Peng KEK (Japan): N. Saito, S. Sawada LANL (USA): M.L. Brooks, X. Jiang, G.L. Kunde, M.J. Leitch, M.X. Liu, P.L. McGaughey RIKEN/RBRC (Japan/USA): Y. Fukao, Y. Goto, I. Nakagawa, K. Okada, R. Seidl, A. Taketani Seoul National Univ. (Korea): K. Tanida Stony Brook Univ. (USA): A. Deshpande Tokyo Tech. (Japan): K. Nakano, T.-A. Shibata Yamagata Univ. (Japan): N. Doshita, T. Iwata, K. Kondo, Y. Miyachi I will mainly discuss the fixed-target experiment LoI whose title is “Measurement of Dimuons from Drell-Yan Process with Polarized Proton Beams and an Internal Target at RHIC” This is the author list of the Letter-of-Intent, which consists of institutes from Taiwan, USA, Japan and Korea. It involve collaborators from Fermilab-E906/SeaQuest, Academia Sinica and Argonne, and from COMPASS, Yamagata Univ. January 21, 2011 23

IP2 (overplotted on BRAHMS) Internal target position St.4 MuID St.1 St.2 St.3 F MAG3.9 m Mom.kick 2.1 GeV/c KMAG 2.4 m Mom.kick 0.55 GeV/c The IP of the IP2 is at the center of this figure. Internal target is assumed to be located at here. 14 meter is available for detector apparatus. The assumption of the momentum kick by the first magnet is 2.1 GeV/c and that by the second magnet is 0.55 GeV/c. These red and green lines show simulated tracks of mu+ and mu- of 100 fast simulation events. 14 m 18 m January 21, 2011 24

Experimental sensitivities PYTHIA simulation s = 22 GeV (Elab = 250 GeV) luminosity assumption 10,000 pb-1 Phase-1 (parasitic operation) 10,000 pb-1 Phase-2 (dedicated operation) 30,000 pb-1 4.5 GeV < M < 8 GeV acceptance for Drell-Yan dimuon signal is studied all generated dumuon from Drell-Yan accepted by all detectors To estimate the experimental sensitivities, we performed a PYTHIA simulation under conditions of E_beam = 250 GeV, or sqrt(s) = 22 GeV and luminosity assumption 10,000 pb^-1.’ For the internal-target experiment, about 10 times larger luminosity is necessary than that of the collider experiments because of about 10 times smaller cross section x acceptance in the same mass region. We investigate dimuon mass region from 4.5 GeV to 8 GeV. The black histogram shows all generated dimuons from Drell-Yan process and the blue histogram shows accepted by the detectors. January 21, 2011 25

Experimental sensitivities About 50K events for 10,000pb-1 luminosity x-coverage: 0.2 < x < 0.5 Mass (GeV/c2) Total Rapidity 45 – 50 50 – 60 60 – 80 45 – 80 -0.4 – 0 3.1 K 1.4 K 7.6 K 0 – 0.4 6.2 K 6.1 K 3.0 K 15.3 K 0.4 – 0.8 6.4 K 2.3 K 16.3 K 0.8 – 1.2 4.4 K 2.5 K 0.4 K 7.3 K x1: x of beam proton (polarized) x2: x of target proton About 50K events are detected in the detector acceptance for 10,000 pb^-1 luminosity. The table shows number of events for each rapidity and dimuon mass bins. This figure show x1 vs x2, where x1 is x of polarized beam proton and x2 is x of target proton. This is a projection to x1 which show expected x-coverage 0.2 < x < 0.5. January 21, 2011 26

Experimental sensitivities Phase-1 (parasitic operation) L = 2×1033 cm-2s-1 10,000 pb-1 with 5×106 s ~ 8 weeks, or 3 years (10 weeks×3) of beam time by considering efficiency and live time Phase-2 (dedicated operation) L = 3×1034 cm-2s-1 30,000 pb-1 with 106 s ~ 2 weeks, or 8 weeks of beam time by considering efficiency and live time Theory calculation: U. D’Alesio and S. Melis, private communication; M. Anselmino, et al., Phys. Rev. D79, 054010 (2009) Measure not only the sign of the Sivers function but also the shape of the funcion From phase1 and phase1+phase2, our expected error bar of the single-spin asymmetry measurement is shown in this figure. It is compared with theory calculation provided by Umberto D’Alesio and Stefano Melis based on the paper by Anselmino’s group. By combining, we want to measure not only the sign of the Sivers function but also the shape of the function. 10,000 pb-1 (phase-1) 40,000 pb-1 (phase-1 + phase-2) January 21, 2011 27

Summary Polarized Drell-Yan measurement The simplest process in hadron-hadron reaction But, not yet done because of technical difficulties so far Sivers function measurement in the valence-quark region from the SSA of Drell-Yan process Test of the QCD prediction “Sivers function in the Drell-Yan process has an opposite sign to that in the DIS process” Milestone for the field of hadron physics RHIC Existing collider experiments (PHENIX/STAR) Two new LoI’s – collider exp. and fixed-target exp. Internal-target polarized Drell-Yan experiment at RHIC 250 GeV transversely polarized proton beam, s = 22 GeV Dimuon spectrometer based on FNAL-E906 spectrometer Measurement not only the sign of the Sivers function, but also the shape of the function feasible This is the summary… January 21, 2011 28

Backup slides

Shipping St.3+ Chamber from Japan to Fermilab Concerns Heat expansion of the metal parts Requirement on the specification document: 10 deg. to 40 deg. in celcius. The package was covered by “PROTECT SHEET” to prevent heat and humidity indide. Gas expansion due to pressure drop in the air May cause breaking of the window sheets. Inner volume of the chamber can be ventilated through the gas inlets/outlets. Shock The chamber was laid down on a flat base with shock-absorbing forms. “Shock wathch” and “Tilt watch” were on the surface of the package to warn workers to handle it carefully. Threshhold of the “Shock watch” was 80G/50msec (Morimatsu L-47). January 21, 2011

Shipping document (RIKEN, July 2, 2010) January 21, 2011

Shipping document (Fermilab, July 20, 2010) January 21, 2011

Shipping: Result ORD to Fermilab (truck) RIKEN to Narita (truck) Narita to ORD (air freighter) Stored near Narita with air conditioning Stored near ORD without air conditioning No wire breaking, no damage on the windows. Temperature: stable, 19.6 (in aircraft) – 29.4 (near ORD) deg. (C) Humidity: low around 20%. Spikes in the aircraft may be due to gas flows caused by pressure change. Shocks: 4.080G on the way from RIKEN to Narita, 4.821G at Narita, 5.770G at O’Hare. Acceleration was detected mainly for the vertical direction. January 21, 2011

Status Component Projected Ready Comments/Issues Beam Line Early to Mid July ???? Target When needed -Aug Magnets Mid June Sta 1 DC October Hodo 1 and 2 1 July Support Structure, Cabling, Electronics Sta 2 DC Ready Cabling, Electronics Absorber wall Needed before Support Structure for 3 and 4 Sta 3 DC – Lower, New Ready, Early July Sta 3 and 4 Scin Early July Support Structure, Electronics Prop Tubes Gas System Pre mix in July as fall back Preamps ????????? TDC’s ?????????? Latches August Trigger Calibration triggers Scalers Not a major effort, but need organizing DAQ ????? January 21, 2011

Fermilab E906/SeaQuest timeline Commissioning with beam from October 2010 Understand Beam Check detector gains and thresholds with minimum ionizing particles Set detector timing Set trigger timing Measure rates in a systematic way – multiple KMAG fields Take data to align spectrometer – KMAG magnet on and magnet off Take data to study trigger matrices Exercise DAQ and analysis chain Phsics run will start in 2010 for 2-year data collection until 2013 January 21, 2011