1. Overview of the EBAC@JLAB progress B. Juliá-Díaz Departament d’Estructura i Constituents de la Matèria Universitat de Barcelona (Spain) The players: ¨ H. Kamano (JLab) ¨ T.S.H. Lee (Argonne, JLab) ¨ A. Matsuyama (Shizuoka) ¨ T. Sato, N. Suzuki (Osaka) ¨ B. Saghai, J. Durand (Saclay)

2. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009

3. Baryon Resonances Exciting the substructure we can learn about the forces which keep the quarks together, e.g. using the quark model picture some of the predicted states are: P11 (939) 0s 0p L=0, S=1/2, J  =1/2 + P33 Δ(1232) L=0, S=3/2, J  =3/2 + S11 (1535) L=1, S=1/2, J  =1/2 - D13 (1520) L=1, S=1/2, J  =3/2 - S31 (1620) L=1, S=1/2, J  =1/2 - D33 (1700) L=1, S=1/2, J  =3/2 - J=1/2 J=3/2 J=1/2 qqq

4. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 The Δ (1232) and others The Delta (1232) resonance stands as a clear peak The region 1.4 GeV – 2 GeV hosts ~ 20 resonances πN  X, πN N*: 1440, 1520, 1535, 1650, 1675, 1680,... Δ : 1600, 1620, 1700, 1750, 1900, … Δ (1232)  100

5. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 PDG *s and N*’s origin Most of their properties are extracted from  N   N  N   N Are they all genuine quark/gluon excitations? |N*> =| qqq > Is their origin dynamical?  E.g. some could be understood as arising from meson-baryon dynamics |N*>= | MB > π N (L IJ ) N*s

6. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Our plan and method

7. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 EBAC@JLAB N* properties N-N* form factors QCDQCDQCDQCD Lattice QCD Hadron Models Dynamical Coupled-Channels Analysis @ EBAC Reaction Data

8. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 E.m. probes e.g:  p  η  Key points: Couplings of mesons to baryons Electromagnetic vertices  Coupling of resonances to MB Electromagnetic structure of resonances e.m.

9. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Multi step (unitarity) How do we produce meson-baryon states? Directly Through MB states Through MMB states  We need to incorporate all the possibilities  Unitarity: Coupled-channels σ TOT (  b) pp MS

10. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 C.C. ingredients Non-resonant + resonant Dressed resonant vertex Resonance self energies Non-resonant amplitude (resummation) CC

11. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 MB  MB We introduce explicitly (impose) a minimal number of resonances, 16 of 23: (4* and 3 * from PDG): N: S11(2), P11(2), P13(1), D13(1), D15(1), F15(1) Δ: S31(1), P31(1), P33(2), D33(1), F35(1), F37(1) CC Full approach described in great detail: A. Matsuyama, T. Sato, T.-S.H. Lee, Phys. Rep. 2007

12. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 i.e. V  N   N,  N CC Full approach described in great detail: A. Matsuyama, T. Sato, T.-S.H. Lee, Phys. Rep. 2007

13. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Resonance t CC Full approach described in great detail: A. Matsuyama, T. Sato, T.-S.H. Lee, Phys. Rep. 2007

14. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Dynamical CC|SL/EBAC ∫vgt Physics: Unitarity fulfilled within the model Most relevant channels included Consistent study of all production reactions Exact treatment of 3 body cut Technical Parallel computing version exists Slow evaluation

15. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Hadronic part (essential starting point)

16. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Meson-baryon building NN (1) SAID Energy dependent PWA with fake error bars (2) SAID Energy independent PWA (3) EXP DATA Bg N* param FIT Fine tune MINUIT used extensively REFIT (almost final)

17. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Technical aspects Involved system of coupled integral equations with singularities. No further approximations taken. Need for extensive parameter search. Several unknowns: e.g. couplings of resonances to MB states  We developed a parallel code, CCEBA, and got several supercomputing resources Tech Time gain resulting from using parallel computers scales ~ linearly with the number of processors  First: parallelization in Energy  Second: parallelization in partial wave  BSC, Spain (340 kh), PI: B. Julia-Diaz  NERSC LBNL (500 kh), PI: TSH Lee

18. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Meson-baryon NN EBAC SAID06

19. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Meson-baryon (ii) B. Julia-Diaz, A. Matsuyama, T.-S.H. Lee, T. Sato, Phys. Rev. C 76, 065201 (2007) data obtained through D. Arndt et al, SAID, gwdac.phys.gwu.edu NN d  /d  Polarization

20. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Meson-baryon (iii)  Amplitudes compared to GWU/SAID amplitudes for the I=1/2 sector  Total Cross sections compared to experimental data  Prediction for the total cross sections for each individual channel B. Julia-Diaz, A. Matsuyama, T.-S.H. Lee, T. Sato, Phys. Rev. C 76, 065201 (2007) Real part of the amplitude NN

21. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009     H. Kamano, B. Julia-Diaz, TSH Lee, A. Matsuyama, T. Sato, Phys. Rev. C 79 (2009) 025206

22. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009    (II)    (Using the MB model of BJD, AM, TSHL and TS, Phys. Rev. C 76, 065201 (2007)) Data handled with the help of D. Arndt Invariant mass distributions Phase space Full model H. Kamano, B. Julia-Diaz, TSH Lee, A. Matsuyama, T. Sato, Phys. Rev. C 79 (2009) 025206

23. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Properties of N*

24. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Analytic continuation of T(W) to the unphysical sheet by using contour deformation Pole can be both in the non-resonant and resonant amplitudes Pole of T as a function of W, p’s are arbitrary Resonance states Extraction of Resonances from Meson-Nucleon Reactions. N. Suzuki, T. Sato, T.-S.H. Lee, Phys. Rev. C 79 (2009) 025205 Resonance Mass

25. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Suzuki, BJD, HK, AM,TSHL, TS, in preparation (2009) Current N*

26. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Electromagnetic part

27. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Single pion production Strong pieces fixed E.g. e.m. vertex of nucleon: fixed  Electromagnetic structure of resonances  Q 2 independent analyses? Error? Which N*s ? All?

28. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Single pion photoproduction B. Julia-Diaz, A. Matsuyama, T.-S.H. Lee, T. Sato, L.C. Smith, Phys. Rev. C77, 045205 (2008) σ TOT (  b) p0pp0p Comparison to data  Total cross section  Differential cross sections  Target polarization p+np+n 

29. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Single pion electroproduction Delta region:  We revisited the original SL model and extracted the form factors of N  Delta transition from single Q 2 fits.  Julia-Diaz, Lee, Sato, Smith, Phys. Rev. C 75, 015205, (2007)

30. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Single pion electroproduction B. Julia-Diaz, A. Matsuyama, T.-S.H. Lee, T. Sato, L.C. Smith, Phys. Rev. C77, 045205 (2008)  On going work:  Fix the strong pieces  Resonance content fixed in strong part  First fit the structure functions available where they have been extracted  First goal is to go up to W=1.65 and Q 2 =4 GeV 2  Current status  Preliminar Q 2 evolution of helicities available  Need to control de error

31. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 In progress (~ 2009) Single and double meson production   *N   N up to W=1.6 GeV (preparation) H. Kamano, B. Julia-Diaz, A. Matsuyama, T.-S.H. Lee, T. Sato  Currently using CLAS structure functions to fix the Q 2 evolution of the helicity amplitudes  PRELIMINARY RESULTS AVAILABLE   *N   N (preparation) B. Julia-Diaz, H. Kamano, A. Matsuyama, T.-S.H. Lee, T. Sato END N* properties  N* properties from the EBAC  N model N. Suzuki, B. Julia-Diaz, H. Kamano, A. Matsuyama, T.-S.H. Lee, T. Sato.  Extraction of N*  MB and N*   N decay vertices B. Julia-Diaz, H. Kamano, A. Matsuyama, T.-S.H. Lee, T. Sato, N. Suzuki

32. B. Julia-Diaz, Overview of the EBAC@JLAB progress, PWA, Bad Honnef 2009 Extraction of Resonances from Meson-Nucleon Reactions. N. Suzuki, T. Sato, T.-S.H. Lee, Phys. Rev. C 79 (2009) 025205 Dynamical coupled-channels study of pi n --> pi pi n reactions H. Kamano, B. Julia-Diaz, T.-S.H. Lee, A. Matsuyama, T. Sato, Phys. Rev. C 79 (2009) 025206 Coupled-channels study of the pion- p --> eta n process J. Durand, B. Julia-Diaz, T.-S.H. Lee, B. Saghai, T. Sato, Phys. Rev. C 78, 025204 (2008) Dynamical coupled-channels effects in pion photoproduction B. Julia-Diaz, T.-S.H. Lee, A. Matsuyama, T. Sato, and L.C. Smith, Phys. Rev. C 77, 045205 (2008) Dynamical coupled-channels model of pi N scattering in the W <= 2-GeV nucleon resonance region. B. Julia-Diaz, T.-S.H. Lee, A. Matsuyama, T. Sato, Phys. Rev. C 76, 065201 (2007)