1. Unpolarized Drell-Yan Experiments at Fermilab and J-PARC Paul E. Reimer 7 April 2008 What do we measure with Drell-Yan? –Selectivity for sea quarks What Physics can we address? –Dbar/ubar –Nuclear modifications –Large-x structure –Parton energy loss –QCD—Lam Tung Relation –Meson Structure (Seonho Choi, NP08) –Polarized Structure (Yuji Goto here, NP’08) How and Where? Goal: Present an overview of Drell-Yan physics at J-PARC and Fermilab

2. 2 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN x target x beam Detector acceptance chooses x target and x beam. Fixed target ) high x F = x beam – x target Valence Beam quarks at high-x. Sea Target quarks at low/intermediate-x. Sea Target quarks at low/intermediate-x. Drell-Yan scattering: A laboratory for sea quarks E906 Spect. Monte Carlo

3. 3 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Advantages of 120 GeV Main Injector The (very successful) past: Fermilab E866/NuSea Data in 1996-1997 1 H, 2 H, and nucl. targets 800 GeV proton beam Fermilab E906 Data in 2009 1 H, 2 H, and nucl. targets 120 GeV proton Beam Cross section scales as 1/s Backgrounds, (J/  and charm decays) scale as s Fixed Target Beam lines Tevatro n 800 GeV Main Injector 120 GeV J-PARC Polarized beams and targets Meson beams 50 GeV proton Beam The Future Within limits

4. 4 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Fermilab E866 Detector Reconstruct M 2 , p T , p ||  M 2  = x 1 x 2 s, x F = 2p ||  /s 1/2 ≈ x 1 – x 2 x 1 ; 2 = 1 2 " ± x F + r x F 2 + 4 M 2 s # Target-to-dump distance important –Acceptance (especially at 50 GeV) –Background from  § decay (especially at 50 GeV) –Target/Dump Separation –Fringe Field (polarized target)

5. 5 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN What is the distribution of sea quarks? In the nucleon: Sea and gluons are important: –98% of mass; 60% of momentum at Q 2 = 2 GeV 2 Not just three valence quarks and QCD. Shown by E866/NuSea d-bar/u-bar data What are the origins of the sea? Significant part of LHC beam. CTEQ6m In nuclei: The nucleus is not just protons and neutrons What is the difference? –Bound system –Virtual mesons affects antiquarks distributions

6. 6 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Light Antiquark Flavor Asymmetry: Brief History Naïve Assumption: NA51 (Drell-Yan) E866/NuSea (Drell-Yan) NMC (Gottfried Sum Rule) Knowledge of distributions is data driven –Sea quark distributions are difficult for Lattice QCD

7. 7 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Models Relate Antiquark Flavor Asymmetry and Spin Meson Cloud in the nucleon—Sullivan process in DIS ¹ d ( x ) ¡ ¹ u ( x ) ¼ ¢ ¹ u ( x ) ¡ ¢ ¹ d ( x ) ¹ d I ( x ) ¡ ¹ u I ( x ) = 3 5 [ ¢ u I ( x ) ¡ ¢ d I ( x )] Z 1 0 £ ¹ d ( x ) ¡ ¹ u ( x ) ¤ = 2 a ¡ b 3 = 0 : 10 ! a = 0 : 2 = 2 b g A = Z 1 0 [ ¢ u ¡ ¢ d ] d x = 5 3 ¡ 20 27 p 2 a b ! 1 : 5 Z 1 0 £ ¹ d ( x ) ¡ ¹ u ( x ) ¤ = 2 a 3 = 0 : 10 ! a = 0 : 14 g A = Z 1 0 [ ¢ u ¡ ¢ d ] d x = 5 3 3 a ! 1 : 43 h q j q i = · 1 ¡ 3 a 2 ¸ h q j q i + 3 a 2 h q¼ j q¼ i Chiral Quark models—effective Lagrangians L / ¹ u R u L ¹ d R d L + ¹ u L u R ¹ d L d R Instantons Statistical Parton Distributions h P j P i = ( 1 ¡ a ¡ b ) h P 0 j P 0 i + a h N 0 ¼ j N 0 ¼ i + b h ¢ 0 ¼ j ¢ 0 ¼ i :::

8. 8 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Something is missing All non-perturbative models predict large asymmetries at high x. Are there more gluons and therefore symmetric anti-quarks at higher x? Does some mechanism like instantons have an unexpected x dependence? (What is the expected x dependence for instantons in the first place?) Perturbative sea apparently dilutes meson cloud effects at large-x

9. 9 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Extracting d-bar/-ubar From Drell-Yan Scattering Sensitivity to d-bar/u-bar depends on kinematics Need high x F for extraction ¾ p d 2 ¾ pp ¯ ¯ ¯ ¯ x F >> 0 ¼ 1 2 · 1 + ¹ d ¹ u ¸

10. 10 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Drell-Yan Absolute Cross Sections ¼ of data represented in plot (alternate decades, alternate targets) Last few x F bins show PDF’s “over predict” NLO cross section

11. 11 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Drell-Yan Absolute Cross Sections: x target Reach high-x through beam proton Large x F ) large x beam. High-x distributions poorly understood –Nuclear corrections are large, even for deuterium –Lack of proton data Proton-Proton –no nuclear corrections –4u(x) + d(x) Preliminary Data are free for analysis after dbar/ubar expt. Both J-PARC and Fermilab will have similar reach in statistics and in x Target.

12. 12 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Structure of nucleonic matter: How do sea quark distributions differ in a nucleus? EMC: Parton distributions of bound and free nucleons are different. Antishadowing not seen in Drell-Yan—Valence only effect What can the sea parton distributions tell us about the effects of nuclear binding? Alde et al (Fermilab E772) Phys. Rev. Lett. 64 2479 (1990) sea Intermediate-x sea PDF’s absolute magnitude set by -DIS on iron. –Are nuclear effects the same for the sea as for valence? –Are nuclear effects with the weak interaction the same as electromagnetic?

13. 13 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Structure of nucleonic matter: Where are the nuclear pions? The binding of nucleons in a nucleus is expected to be governed by the exchange of virtual “Nuclear” mesons. No antiquark enhancement seen in Drell-Yan (Fermilab E772) data. Contemporary models predict large effects to antiquark distributions as x increases. Models must explain both DIS- EMC effect and Drell-Yan Models must explain both DIS- EMC effect and Drell-Yan

14. 14 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Nuclear Antiquark Sea measured at J-PARC J-PARC can extend reach to significantly higher x First test QCD Factorization at low energy--must be valid. Bodwin, Brodsky and LePage PRD 39, 3287 (1989). Study higher-twist effects Extend reach to higher x P m i n ¼ p T A 2 = 3 x 1

15. 15 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Partonic Energy Loss 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 (x 1 or x F ) is shifted Fit shift in x 1 relative to deuterium Models: –Galvin and Milana –Brodsky and Hoyer –Baier et al. X1X1 X1X1

16. 16 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Partonic Energy Loss E866 data are consistent with NO partonic energy loss for all three models E866 data are consistent with NO partonic energy loss for all three models Caveat: A correction must be made for shadowing because of x 1 —x 2 correlations –E866 used an empirical correction based on EKS fit do DIS and Drell-Yan. E866/NuSea Treatment of parton propagation length and shadowing are critical –Johnson et al. find 2.7 GeV/fm (≈1.7 GeV/fm after QCD vacuum effects) –Same data with different shadowing correction and propagation length Better data outside of shadowing region are necessary.

17. 17 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Parton Energy Loss Shift in  x / 1/s Even larger at 50 GeV –Larger at 120 GeV; Even larger at 50 GeV Sufficient statistics to cut shadowing region, x 2 < 0.1, from data. Energy loss upper limits based on E866 Drell-Yan measurement E906 uncertainties Shadowing region removed J-PARC 50 GeV

18. 18 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Meson Drell-Yan (Seonho Choi, Seoul, NP08) High-x  parton distributions –High-x from of (1-x)  –Predictions for  from Dyson-Schwinger, pQCD and Nambu-Jona-Lasinio models –Data fall predictions, but poor x  resolution Charge symmetry violation  + /  - on deuterium target –Difficulty producing pure  + beam Kaon Parton Distributions Need 50 GeV beam for reasonable meson energy (my opinion) Low secondary beam flux –Dump and magnet possibly not necessary (Needs simulation) –Increase acceptance by moving spectrometer forward J-PARC only J-PARC only

19. 19 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Generalized Angular Distributions Chi-Sing Lam and Wu-Ki Tung—basic formula for lepton pair production angular distributions PRD 18 2447 (1978) Lam-Tung Relation Direct analogy to the Callan-Gross relation in DIS Normally written as Unaffected by O(  s ) (NLO) corrections NNLO [O(  s 2 )] corrections also small Mirkes and Ohnemus, PRD 51 4891 (1995) Also holds under resummation Berger, Qiu, Rodriguez- Pedraza, PRD 76, 074006 (2007) Robust Prediction of QCD Helped to validate the Drell-Yan picture of quark-antiquark annihilation for lepton pair production d ¾ d ­ / 1 + ¸ cos 2 µ + ¹s i n 2 µ cos Á + º 2 s i n 2 µ cos 2 Á 1 ¡ ¸ = 2 º

20. 20 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Lam-Tung Relation  - Drell-Yan –Violates L-T relation –Large (cos2  ) dependence –Strong with p T Proton Drell-Yan –Consistent with L-T relation –No (cos2  ) dependence –No p T dependence Alternative: Higher twist √s dependence—need J-PARC test Boer-Mulders function h 1 ? : –  (  W !  +  - X) Valence h 1 ? (  ) £ valence h 1 ? (p) –  (pd !  +  - X) Valence h 1 ? (p) £ sea h 1 ? (p) –J-PARC—both w/same Spectrometer

21. 21 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Transversely Polarized Target or beam Sivers’ distribution f ? 1T (x, k T ) Single spin asymmetry Possibly explanation for E704 data Collins Fragmentation function could also produce such an asymmetry Fermilab E704, Phys. Rev. Lett. 77, 2626 (1996) HERMES has observed both effects in SIDIS With Drell-Yan: f ? 1T (x, k T )| DIS = - f ? 1T (x, k T )| D-Y With transversely polarized target one measures sea quarks Sea quark effects might be small See talk by Dr. Yuji Goto J-PARC ONLY

22. 22 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Drell-Yan timeline Fermilab PAC approved the experiment in 2001, but experiment was not scheduled due to concerns about “proton economics” Spectrometer upgrade funded by DOE/Office of Nuclear Physics (already received $538k in FY07) Fermilab PAC reaffirms earlier decision in Fall 2006 Scheduled to run in 2010 for 2 years of data collection 2009 2008 2011 Publications Expt. Funded 2010 Magnet DesignExperiment And constructionConstruction Proposed Jan. 2007 Experiment Runs J-PARC 2012 Apparatus available for future program at J-PARC –Significant interest from collaboration for continued program here

23. 23 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Drell-Yan at Fermilab and J-PARC d-bar/u-bar –Fermilab and extended range from J-PARC 50 GeV –The origins of the sea quarks? –The high-x structure of the proton? Antiquarks in Nuclei Do colored partons lose energy in cold nuclear matter? Meson Drell-Yan (J-PARC) Polarized Drell-Yan (J-PARC)

24. 24 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Additional Material

25. 25 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN FNAL E866/NuSea Collaboration Abilene Christian University Donald Isenhower, Mike Sadler, Rusty Towell, Josh Bush, Josh Willis, Derek Wise Argonne National Laboratory Don Geesaman, Sheldon Kaufman, Naomi Makins, Bryon Mueller, Paul E. Reimer Fermi National Accelerator Laboratory Chuck Brown, Bill Cooper Georgia State University Gus Petitt, Xiao-chun He, Bill Lee Illinois Institute of Technology Dan Kaplan Los Alamos National Laboratory Melynda Brooks, Tom Carey, Gerry Garvey, Dave Lee, Mike Leitch, Pat McGaughey, Joel Moss, Brent Park, Jen-Chieh Peng, Andrea Palounek, Walt Sondheim, Neil Thompson Louisiana State University Paul Kirk, Ying-Chao Wang, Zhi-Fu Wang New Mexico State University Mike Beddo, Ting Chang, Gary Kyle, Vassilios Papavassiliou, J. Seldon, Jason Webb Oak Ridge National Laboratory Terry Awes, Paul Stankus, Glenn Young Texas A & M University Carl Gagliardi, Bob Tribble, Eric Hawker, Maxim Vasiliev Valparaiso University Don Koetke, Paul Nord

26. 26 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Fermilab E906/Drell-Yan Collaboration Abilene Christian University Donald Isenhower, Mike Sadler, Rusty Towell 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 Jaing, Elena Kuchina, Ron Ransome, Elaine Schulte Texas A & M University Carl Gagliardi, Robert Tribble Thomas Jefferson National Accelerator Facility Dave Gaskell Valparaiso University Don Koetke, Jason Webb Pending Collaborators RIKEN Yuji Goto, Atsushi Taketani, Yoshinori Fukao, Manabu Togawa Kyoto University KenIchi Imai, Tomo Nagae Tokyo Tech Toshi-Aki Shibata, Yoshiyuki Miyachi KEK Shin'ya Sawada

27. 27 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Collaboration: Measurement of High-Mass Dimuon Production at the 50-GeV Proton Synchrotron Brookhaven National Laboratory M. Bai, H. Huang, A. U. Luccio, T. Roser, A. Zelenski University of Illinois R. Seidl, M. Grosse Perdekamp, J.-C. Peng KEK S. Ishimoto, C. Ohmori, A. Molodojentsev, N. Saito, H. Sato*, S. Sawada, J. Takano Kyoto University K. Imai Los Alamos National Laboratory M. Brooks, X. Jiang, G. Kunde, M. J. Leitch, M. X. Liu, P. L. McGaughey Osaka University K. Hatanaka RIKEN Y. Fukao, Y. Goto*, A. Taketani, M. Togawa Rikkyo University K. Kurita, Tokyo Tech T.-A. Shibata Tokyo University J. Chiba Yamagata University N. Doshita, T. Iwata, K. Kondo

28. 28 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Collaboration: Polarized Proton Acceleration at J-PARC Abilene Christian University L. D. Isenhower, M. Sadler, R. Towel Argonne National Laboratory P. E. Reimer Duke University D. Dutta, H. Gao University of Illinois J.-C. Peng* KEK S. Sawada*, K. H. Tanaka Kyoto University N. Saito Los Alamos National Laboratory M. J. Leitch, M. X. Liu, P. L. McGaughey RIKEN Y. Goto Tokyo Tech T.-A. Shibata Tokyo University J. Chiba Yamagata University T. Iwata, S. Kato, H. Y. Yoshida

29. 29 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Next-to-Leading Order Drell-Yan Next-to-leading order diagrams complicate the picture These diagrams are responsible for 50% of the measured cross section Intrinsic transverse momentum of quarks (although a small effect, > 0.8)

30. 30 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Kulagin and Petti sea vs. valence nuclear effects Valence Sea Nuclear Physics A 765 (2006) 126–187

31. 31 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Aside: Rescaling Models in Trouble? Prediction of  mass/width modification not seen in JLab/CLAS data Nasseripour et al. (CLAS) PRL 99, 262302 (2007)

32. 32 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Proton Valence Structure: Unknown as x ! 1 Theory Exact SU(6): d/u ! 1/2 Diquark S=0 dom.:d/u ! 0 pQCD: d/u ! 3/7 Data Binding/Fermi Motion effects in deuterium—choice of treatments. Proton data is needed.Proton data is needed. Petratos et al. nucl-ex/0010011 Relative uncertainty up- quark distribution (CTEQ6e) Reality: We don’t even know the u or d quark distributions—there really is very little high-x proton data

33. 33 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Drell-Yan Absolute Cross Sections: x target Measures a convolution of beam and target PDF absolute magnitude of high-x valence beam distributions absolute magnitude of the sea in the target –Currently determined by –Fe DIS Preliminary

34. 34 7 April 2008Paul E. Reimer--J-PARC Meeting for Spin and Hadron Physics at RIKEN Detector Rates Expected single muon rates per 2 £ 10 12 protons from decay-in-flight mesons which pass through the detector (  's) and satisfy trigger matrix tracking requirements (Trks.) from liquid hydrogen and deuterium targets and the copper beam dump.