核子構造：J-PARC実験 Shin’ya Sawada KEK (High Energy Accelerator Research Organization, Japan) August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Shin'ya Sawada @ J-PARC Workshop, KEK メニュー 核子の形？ ビジュアルでわかりたい straw man の素朴な疑問 実験 これまでの実験 これからの実験 Fermilab E906 J-PARC Proposals：主としてP04 施設 ビームライン まとめ August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Shin'ya Sawada @ J-PARC Workshop, KEK 核子の形？（ビジュアル系な素朴な疑問） 核子＝３つのバレンスクォーク(?) 形は？球形？？“均一”？？？ 核の中の核子の形は？ シークォーク(sea quark)の分布はどうなってるの？ average spacing at ρnm ~ 1.8 fm Radius of a nucleon ~ 0.8 fm average spacing at 3ρnm ~ 1.3 fm “nucleons” held apart by short range repulsion but even in 208Pb, half the nucleons are in the surface or August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Shin'ya Sawada @ J-PARC Workshop, KEK 核子の形？（ビジュアル系な素朴な疑問） スピンでラベルしたときの形は？ G. A. Miller, Phys. Rev. C68, 022201(R) (2003) Spin dependent density operator Shapes of the proton. Proton spin is vertical direction. Left column: quark spin parallel to proton spin. Right column: quark spin anti-parallel to proton spin. K (quark momentum): 1 to 4 GeV/c (from upper to lower). G. A. Miller, Phys. Rev. C76, 065209 (2007) Transverse momentum dependent parton density and spin dependent density operator ゼロでないBoer-Mulders fn.  非球形のspin dependent density S q q Boer-Mulders Fn.（をxについて積分した関数）： Drell-Yan で測定可能 August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Shin'ya Sawada @ J-PARC Workshop, KEK 実験 レプトン－核子・核 SLAC、DESY、CERN、…、Jlab 核子－核子・核 衝突型加速器：RHIC 固定標的実験: 米国フェルミ研 E605, E772 (-1988), E789 (-1991), E866 (-1996) E906 (going) p+p/d/A  mu+ mu- X ：ミュオン対の測定。 Drell-Yan 過程やQuarkonium生成を観測する。 比較的大きなｘ。 sea quark の分布に有感。 August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Fermilab Experiments Meson East Spectrometer (E605/772/789/866) Open-aperture Closed-aperture Beam-dump (Cu) J/Ψ J/Ψ Ψ’ σ(J/ψ) ~ 15 MeV σ(J/ψ) ~ 150 MeV σ(J/ψ) ~ 300 MeV

Fermilab E866 Detector: Long History E605: 1978-1985 US-Japan Study of single and pair production of leptons and hadrons at very high transverse momenta E772: 1986-1988 Nuclear dependence of DY and quarkonium production E789: 1989-1991 Search for two body decay of heavy quark mesons E866/Nusea: 1993-1996 Determination of d-bar/u-bar ratio of the proton via DY August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Physics with High-Mass Dimuons with unpol beam/target Drell-Yan process Antiquarks in nuclei and nucleons Quark energy loss in nuclear medium Drell-Yan angular distributions Toward spin related structure Quarkonium production Pronounced nuclear dependence Production mechanism and polarization Parton distribution in the nucleon Heavy quark production Open charm production B-meson production Drell-Yan: ハドロン衝突で最も単純な過程 QCDからのfinal-state effectがない 偏極Drell-Yan実験はこれまで行なわれていない August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Structure of the Nucleon Sea: Previous Data pQCD – Gluon splitting? i.e. NMC (Gottfried Sum Rule) NA51 (Drell-Yan) E866 (Drell-Yan) August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

By What Process Is the Sea Created? There is a gluon splitting component which is symmetric Symmetric sea via pair production from gluons subtracts off No Gluon contribution at 1st order in s Nonperturbative models are motivated by the observed difference A proton with 3 valence quarks plus glue cannot be right at any scale!! August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

By What Process Is the Sea Created? Meson Cloud in the nucleon Sullivan process in DIS |pi = |p0i +  |Ni + |i + . . . Chiral Models Interaction between Goldstone Bosons and valence quarks |ui!|d+i and |di!|u-i Instanton Statistical Models Models cannot explain d-bar < u-bar! August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

By What Process Is the Sea Created? Meson Cloud in the nucleon Sullivan process in DIS |pi = |p0i +  |Ni + |i + . . . Models cannot explain d-bar/u-bar < 1! Perturbative sea apparently dilutes meson cloud effects at large-x August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Drell-Yan: A Laboratory for Sea Quarks xtarget xbeam Detector acceptance chooses xtarget and xbeam. Fixed target ) high xF = xbeam – xtarget Valence Beam quarks at high-x. Sea Target quarks at low/intermediate-x August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Drell-Yan: What do we really measure? Measure yields of +- pairs from different targets For each event measure 3-momentum of each  Assume that it is a muon to get 4-momentum Reconstruct M2, pT, p|| M2 = x1x2s, xF = 2p||/s1/2 = x1 – x2 August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

dbar/ubar at Large x using 50 GeV Protons DY cross section is ~16 times larger at 50 GeV than at 800 GeV. J-PARC can measure d-bar/u-bar at larger x. August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Shin'ya Sawada @ J-PARC Workshop, KEK 実験プロポーザルとストラテジー Fermilab E906: Main Injector with 120-GeV protons 2010-2012 Mid x region, really d-bar/u-bar < 1?? J-PARC P04: Experiment with 30 and 50-GeV protons 2012- Experimental apparatus mainly from E906 Ep = 30 GeV at the beginning J/Psi physics Ep = 50 GeV at the next stage with unpol beams for higher x Polarized target and / or polarized beams New proposal is under preparation. August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Fermilab E906/Drell-Yan Collaboration Abilene Christian University Donald Isenhower, Mike Sadler, Rusty Towell Institute of Physics, Academia Sinica Wen-Chen Chang, Yen-Chu Chen, Da-Shung Su Argonne National Laboratory John Arrington, Don Geesaman*, Kawtar Hafidi, Roy Holt, Harold Jackson, David Potterveld, Paul E. Reimer*, Patricia Solvignon University of Colorado Ed Kinney Fermi National Accelerator Laboratory Chuck Brown University of Illinois Naomi C.R Makins, Jen-Chieh Peng *Co-Spokespersons Ling-Tung University Ting-Hua Chang Los Alamos National Laboratory Gerry Garvey, Mike Leitch, Pat McGaughey, Joel Moss Maryland Betsy Beise Rutgers University Ron Gilman, Charles Glashausser, Xiaodong Jiang, Elena Kuchina, Ron Ransome, Elaine Schulte Texas A & M University Carl Gagliardi, RobertTribble Thomas Jefferson National Accelerator Facility Dave Gaskell Valparaiso University Don Koetke, Jason Webb Institutions under negotiation KEK Shinya Sawada Kyoto KenIchi Imai, Tomofumi Nagae RIKEN Yuji Goto, Atsushi Taketani, Yoshinori Fukao, Manabu Togawa Tokyo Tech Toshi-Aki Shibata, Yoshiyuki Miyachi 求む！（優秀な？）ポスドク！！ People with underline are included also in P04 and/or P24 at J-PARC. August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Advantages of 120 GeV Main Injector The (very successful) past: Fermilab E866/NuSea Data in 1996-1997 1H, 2H, and nuclear targets 800 GeV proton beam The future: Fermilab E906 Data in 2010-12 1H, 2H, and nuclear targets 120 GeV proton Beam Cross section scales as 1/s 7 x that of 800 GeV beam Backgrounds, primarily from J/ decays scale as s 7 x Luminosity for same detector rate as 800 GeV beam 50 x statistics!! Fixed Target Beam lines Tevatron 800 GeV Main Injector 120 GeV August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Shin'ya Sawada @ J-PARC Workshop, KEK Spectrometer Fermilabでのこれまでの財産を最大限生かして（使える部品はみんな使って）作る。 800GeVでのこれまでの実験に比べ、長さを短く、apertureを出来るだけ広く。 2台のbending magnet、pT kick 2.5GeV/cと0.5GeV/c。 August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Shin'ya Sawada @ J-PARC Workshop, KEK E906でのd-bar/u-bar August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

needs 30 and 50 GeV, 1012 protons per sec. P04: Measurement of High-Mass Dimuon Production at the 50-GeV Proton Synchrotron Collaboration Abilene Christian University, Argonne National Laboratory, Duke University, High Energy Accelerator Research Organization, University of Illinois at Urbana-Champaign, Kyoto University, Los Alamos National Laboratory, Pusan National University, RIKEN, Seoul National University, Tokyo Institute of Technology, Tokyo University of Science, Yamagata University Collaboration members J.K. Ahn, J. Chiba, Seonho Choi, D. Dutta, H. Gao, Y. Goto, L.D. Isenhower, T. Iwata, S. Kato,M.J. Leitch, M.X. Liu, P.L. McGaughey, J.C. Peng, P. Reimer, M. Sadler, N. Saito, S. Sawada,T.-A. Shibata, K.H. Tanaka, R. Towell, H.Y. Yoshida needs 30 and 50 GeV, 1012 protons per sec. Fermilab E906のSpectrometerをJ-PARCに運び、実験する。 最初は30GeV陽子ビーム、続いて50GeV陽子ビーム。 偏極標的や偏極ビームでの実験についても触れているが、これらについては本格的なプロポーザルを準備中。 August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Physics with High-Mass Dimuons with unpol beam/target Drell-Yan process [50GeV] Antiquarks in nuclei and nucleons Quark energy loss in nuclear medium Drell-Yan angular distributions Toward spin related structure Quarkonium production [30GeVでも] Pronounced nuclear dependence Production mechanism and polarization Parton distribution in the nucleon Heavy quark production Open charm production B-meson production Drell-Yan: ハドロン衝突で最も単純な過程 QCDからのfinal-state effectがない 偏極Drell-Yan実験はこれまで行なわれていない August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Antiquarks in nucleons dbar/ubar at Large x using 50 GeV Protons. J-PARC can measure d-bar/u-bar at larger x. August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Quark energy loss in nuclear medium An understanding of partonic energy loss in both cold and hot nuclear matter is paramount to elucidating RHIC data. Pre-interaction parton moves through cold nuclear matter and looses energy. Apparent (reconstructed) kinematic values (x1 or xF) is shifted Fit shift in x1 relative to deuterium August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Quark Energy Loss with DY at 50 GeV At 50 GeV, energy loss can be well measured. Fractional energy loss is larger at 50 GeV. Effect is amplified. Possible to test the L dependence of the LPM effect from the A dependence. August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Drell-Yan angular distributions Boer-Mulders function h1(x, kT2) angular distribution of unpolarized Drell-Yan correlation between transverse quark spin and quark transverse momentum in an unpolarized proton August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Drell-Yan angular distributions With Boer-Mulders function h1┴: ν(π-Wµ+µ-X)~valence h1┴(π)*valence h1┴(p) ν(pdµ+µ-X)~valence h1┴(p)*sea h1┴(p) L.Y. Zhu,J.C. Peng, P. Reimer et al., Phys. Rev. Lett. 99, 082301(2007). 非偏極実験ながらスピンでラベルした核子の構造にも手が届く！ August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Quarkonium production at 30 GeV J/ gluon fusion or quark-pair annihilation quark-pair annihilation dominant? must be confirmed experimentally… similar physics topics as Drell-Yan process calculations by color-evaporation model eq  J/ August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Quarkonium production at 30 GeV L. Y. Zhu et al., Phys.Rev.Lett.100, 62301 (2008). pdとppの比の（エネルギーによる）変化を測定することにより、生成過程を明らかに出来る。 もしも30GeVでq+qbarが支配的なら、J/Psi生成を核子構造の測定に用いることが出来る。 August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Shin'ya Sawada @ J-PARC Workshop, KEK Current Status FNAL E906 Experiment Similar experiment using 120 GeV protons (p+p, p+d, and probably p+A) Scientifically approved Preparation continues, seeking Japanese participation Expect experiment runs from 2010, for 2 years Apparatus is considered to be shipped to Japan after E906 Reuse at J-PARC is being considered in the design J-PARC Experiment even after E906 Difference of beam energy should be important Lower energies lead to extension of large x region, clearer measurement of energy loss, … Check of consistency Quarkonium production Also fruitful, and more complete understanding of the nucleon structure with polarized beams in the future. August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Shin'ya Sawada @ J-PARC Workshop, KEK 偏極ビーム・標的が利用可能になったら… J-PARC dimuon 実験のスピン物理メニュー 縦偏極 ALL of Drell-Yan sea-quark 偏極のフレーバー非対称性 横偏極 AN of Drell-Yan Sivers関数（sin(-S) term） transversity分布関数 & Boer-Mulders関数（sin(+S) term） 横偏極 ATT of Drell-Yan transversity分布関数 その他（30-GeV） J/: Drell-Yan と同様のメニュー? AN of open charm: Sivers関数 (neutron-tagged Drell-Yan) August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Shin'ya Sawada @ J-PARC Workshop, KEK 偏極ビーム・標的？ P24として提案→「実験と装置・施設を分けよ」→新しいプロポーザルへ。 unpolarized  polarized target  polarized beam polarized beam study by BNL & KEK groups possible locations of partial snakes in MR First 30% snake Second 30% snake August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Shin'ya Sawada @ J-PARC Workshop, KEK ビームライン August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Slow Extraction Beamline (Phase 1) NP-HALL 56m(L)×60m(W) 50-GeV PS A-Line Switch Yard Split Point 2% Loss T1 Target 30% Loss T0 Target 0.5% Loss Beam Dump 750kW Plan to extend the hall downstream (~50m) in the Phase 2. August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

What is the High Momentum Beamline? Primary beams: proton (Phase 1), polarized proton and heavy ions (future) up to 51 GeV/c. Secondary beams: proton, pion, kaon, etc. Vector meson production実験（四日市さん、明日）にも不可欠。 The radiation shielding of the SY tunnel is designed so that 2% (15kW) loss allowed at SM1. Here is the essence of our letter of intent. We would like to propose to construct a high momentum bemline originated from the SM1 point, which can accommodate primary beams and secondary beams up to 51 GeV/c. Primary beams mean protons at Phase 1, and polarized protons and heavy ions in the future. Secondary beams are such as protons, pions, kaons, anti-protons and so on. The radiation shielding of the switch-yard tunnel is designed so that a loss of 2% of the total primary beam can be permitted. The high momentum beam line originates this SM1, and its length is about 120m. In the NP hall around here, the experimental apparatus will be located. This beam line could be shared by more than one experiments with staged experimental targets. Exp. setup could be staged. ~120m August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Beamlines at the Hadron Hall August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Shin'ya Sawada @ J-PARC Workshop, KEK Oct. Dec. Neutrino August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

R&D for a bent crystal system p CsI plate ±20 cm Ceramic plate Al plate Goniometer ±o Ceramic plates Distance 145cm Test experiment at KEK-PS (12-GeV proton) ceramic plate (10x10cm) CsI plate (5x2.5cm) goniometer bent crystal main beam deflected beam view from above crystal deflection angle 12GeV protons 1012/s  107/s Grant-in-Aid for a next step R&D of high-mom beamline is being applied: Bent crystal, ESS, … August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Cost & Schedule: Magnets from the World Total cost if constructed from scratch: $5-8M?? We have no budget so far to construct a high momentum beam line. But we are doing every effort to construct it with as small cost as possible, e.g. reuse of second-hand magnets… Already from SLAC, Saclay, CERN, … Large dipole magnets from ANL (previously used for the polarized beam line at FNAL) are under process! The high momentum beam line can be constructed by using some of these second-hand magnets. The high momentum beam line can be constructed even at the beginning of the hadron hall operation from the viewpoint of the facility design. How much is the cost?? We have not made detailed cost estimate, but roughly the total cost would be about 5 million dollars or 8 million, if we construct the beam line from scratch. We have no budget so far to construct a high momentum beam line, but we are doing every effort to construct it with as small cost as possible. For example, we plan to reuse second-hand magnets. Thanks to the efforts of people all over the world, we have already collected many magnets from SLAC, Saclay, CERN etc. Recently we are proceeding to transport large dipole magnets from Argonne. This is a photograph of the magnets located at Fermilab, and they were originally used at Zero Gradient Synchrotron and then used for a polarized beam line at Fermilab. These magnets are really useful for us. In addition, it should be emphasized that the high momentum beam line can be constructed even at the beginning of the NP hall operation from the viewpoint of the facility design. Large dipole magnets at the Meson Pol beam line (FNAL) August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Shin'ya Sawada @ J-PARC Workshop, KEK Summary 核子の構造の研究は、ハドロン物理の王道（のひとつ）。 高エネルギーでの「小さいｘ」だけでなく、“低”エネルギーでの「大きいｘ」領域も重要。 J-PARC 50GeV でのdimuon測定は、 Drell-Yan過程やJ/Psi生成の観測を通じて、sea quark のフレーバー非対称性、パートンのエネルギー損失、等々ハドロンをパートンレベルで研究するためにうってつけの方法である。 Fermilabでは120GeVでのE906実験が進もうとしている。この実験装置をJ-PARCに運び、より低いビームエネルギーで実験することを目指している。 Dimuon測定は、偏極ビームや偏極標的が使用可能になると、より物理的な意義が深まる。 「高運動量ビームライン」はこの実験を実現する上で必要不可欠なビームラインである。また、p+pphi+Xの実験にも必要である。「分岐部」が技術的にもっとも困難であるが、地道にR&Dを進めている。 August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK

Physics with High-Mass Dimuons at J-PARC August 8, 2008 Shin'ya Sawada @ J-PARC Workshop, KEK