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N* analysis at the Excited Baryon Analysis Center of JLab

N* analysis at the Excited Baryon Analysis Center of JLab. Hiroyuki Kamano (EBAC, Jefferson Lab). CLAS12 2 nd European Workshop, March 7-11, Paris, France. “Dynamical coupled-channels model of meson production reactions”. A. Matsuyama, T. Sato, T.-S.H. Lee Phys. Rep. 439 (2007) 193.

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N* analysis at the Excited Baryon Analysis Center of JLab

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  1. N* analysis at the Excited Baryon Analysis Center of JLab Hiroyuki Kamano (EBAC, Jefferson Lab) CLAS12 2nd European Workshop, March 7-11, Paris, France

  2. “Dynamical coupled-channels model of meson production reactions” A. Matsuyama, T. Sato, T.-S.H. Lee Phys. Rep. 439 (2007) 193 Excited Baryon Analysis Center (EBAC) of Jefferson Lab http://ebac-theory.jlab.org/ Founded in January 2006 Reaction Data • Objectives and goals: • Through the comprehensive analysis • of world dataof pN, gN, N(e,e’) reactions, • Determine N* spectrum (pole positions) • Extract N* form factors (e.g., N-N* e.m. transition form factors) • Provide reaction mechanism information necessary forinterpreting N* spectrum, structures and dynamical origins Dynamical Coupled-Channels Analysis @ EBAC N* properties Hadron Models Lattice QCD QCD

  3. Dynamical coupled-channels model For details see Matsuyama, Sato, Lee, Phys. Rep. 439,193 (2007) • Partial wave (LSJ) amplitude of a  b reaction: • Reaction channels: • Transition potentials: coupled-channels effect exchange potentials of ground state mesons and baryons bare N* states

  4. Stage 1 Construct a reaction model through the comprehensive analysis of meson production reactions Requires careful analytic continuation of amplitudes to complex energy plane  Suzuki, Sato, Lee PRC79 025205; PRC82 045206 Stage 2 Extract resonance informationfrom the constructed reaction model • N* spectrum (poles); N*  gN, MB transition form factors (residues) • Confirm/reject N* with low-star status; Search for new N* Stage 3 Make a connection to hadron structure calculations; Explore the structure of the N* states. • Quark models, Dyson-Schwinger approaches, Holographic QCD,… Strategy for N* study at EBAC

  5. EBAC-DCC analysis (2006-2009) pN, hN, ppN (pD,rN,sN) coupled- channels calculations were performed. Hadronic part • p N  pN : Used forconstructing a hadronic model up to W = 2 GeV. Julia-Diaz, Lee, Matsuyama, Sato, PRC76 065201 (2007) • p N  h N : Used for constructing a hadronic model up to W = 2 GeV Durand, Julia-Diaz, Lee, Saghai, Sato, PRC78 025204 (2008) • p N  pp N : First fully dynamical coupled-channels calculation up toW = 2 GeV. Kamano, Julia-Diaz, Lee, Matsuyama, Sato, PRC79 025206 (2009) • g(*) N  p N : Used for constructing a E.M. model up to W = 1.6 GeV and Q2 = 1.5 GeV2 (photoproduction) Julia-Diaz, Lee, Matsuyama, Sato, Smith, PRC77 045205 (2008) (electroproduction)Julia-Diaz, Kamano, Lee, Matsuyama, Sato, Suzuki, PRC80 025207 (2009) • g N  pp N : First fully dynamical coupled-channels calculation up to W = 1.5 GeV. Kamano, Julia-Diaz, Lee, Matsuyama, Sato, PRC80 065203 (2009) Electromagnetic part

  6. pole A: pD unphys. sheet pole B: pD phys. sheet Dynamical coupled-channels effect on N* poles and form factors Suzuki, Julia-Diaz, Kamano, Lee, Matsuyama, Sato, PRL104 065203 (2010) Suzuki, Sato, Lee, PRC82 045206 (2010) Pole positions and dynamical origin of P11 resonances

  7. Crucial role of non-trivial multi-channel reaction mechanisms for interpreting the structures and dynamical origins of nucleon resonances ! Dynamical coupled-channels effect on N* poles and form factors Suzuki, Julia-Diaz, Kamano, Lee, Matsuyama, Sato, PRL104 065203 (2010) Suzuki, Sato, Lee, PRC82 045206 (2010) Nucleon - 1st D13 e.m. transition form factors Real part Imaginary part

  8. EBAC-DCC analysis: 2010 ~ Fully combinedanalysis of gN , N  N , hN , KY reactions !! 2010 ~ 7 channels (pN,hN,pD,rN,sN,KL,KS) < 2.1 GeV < 2 GeV < 2 GeV < 2GeV < 2.1 GeV < 2.1 GeV 2006 ~ 2009 5 channels (pN,hN,pD,rN,sN) < 2 GeV < 1.6 GeV < 2 GeV ― ― ― • # of coupled channels • N  N • gN  N • N hN • gN hN • pN KY • gN KL

  9. Pion-nucleon elastic scattering Angular distribution Target polarization 1234 MeV 1449 MeV 1678 MeV 1900 MeV Current model (fully combined analysis, preliminary) Previous model (fitted to pN  pN dataonly) [PRC76 065201 (2007)]

  10. Angular distribution Photon asymmetry 1154 MeV 1232 MeV 1334 MeV 1313 MeV 1154 MeV 1232 MeV 1313 MeV 1137 MeV 1232 MeV 1334 MeV 1137 MeV 1232 MeV 1462 MeV 1416 MeV 1527 MeV 1519 MeV 1617 MeV 1617 MeV 1416 MeV 1462 MeV 1519 MeV 1527 MeV 1617 MeV 1617 MeV 1729 MeV 1690 MeV 1834 MeV 1798 MeV 1958 MeV 1690 MeV 1899 MeV 1729 MeV 1834 MeV 1958 MeV 1798 MeV 1899 MeV Single pion photoproduction Preliminary!! Current model (fully combined analysis, preliminary) Previous model (fitted to gN  pN data up to 1.6 GeV) [PRC77 045205 (2008)]

  11. 1535 MeV 1549 MeV 1674 MeV 1657 MeV 1811 MeV 1787 MeV 1930 MeV 1896 MeV Eta production reactions Photon asymmetry Preliminary!! • Analyzed data up to W = 2 GeV. • p- p  h n data are selected following Durand et al. PRC78 025204.

  12. Angular distribution 1732 MeV 1757 MeV 1792 MeV 1732 MeV 1792 MeV 1757 MeV 1845 MeV 1879 MeV 1879 MeV 1845 MeV 1879 MeV 1879 MeV 1985 MeV 1966 MeV 1966 MeV 1985 MeV 1966 MeV 1966 MeV 2031 MeV 2059 MeV 2059 MeV 2031 MeV 2059 MeV 2059 MeV pi N  KY reactions Preliminary!! Recoil polarization

  13. gamma p  K+ Lambda Preliminary!! 1781 MeV 1883 MeV 2041 MeV

  14. Energy-independent multipole analysis of the existing gp  K+Ldata: • Take real and imaginary parts of amplitudes as parameters at each energy point • Monte Carlo sampling of L = 0 - 3 amplitudes (up to 107per energy) + gradient minimization = Data available for gp  K+L Potential impact of the complete experiments Sandorfi, Hoblit, Kamano, Lee arXiv:1010.0455 Observables of pseudoscalar photoproduction reactions

  15. Generate mock data with kinematics and errors expected in the CLAS experiments and repeat the analysis To narrow the bands, • should increase statistics of the 8 observables ?? OR • should measure all the remainingpolarization observables?? Potential impact of the complete experiments Sandorfi, Hoblit, Kamano, Lee arXiv:1010.0455 Bands of the best 300 multipole solutions  0.05  0.03  0.10  0.08  0.18 E0+ Real part Difference between Best and Largest c2 M1+ • Overall phase is fixed by setting E0+ real. • Wide solution bands with tightly clustered c2  Solutions are indistinguishable within the existing data. Imaginary part

  16. Potential impact of the complete experiments Sandorfi, Hoblit, Kamano, Lee arXiv:1010.0455 W = 1900 MeV (Energy-independent fit to mock data) c2 / data = 0.6 (best c2 solution) c2 / data = 1.4 (largest c2 solution in the best 300 solutions) [Note:Central values of data are generated with the(Gaussian-smeared) Bonn-Gatchina amplitudes.]

  17. “Complete experiments” at CLAS A crucial source for determining amplitudes and establishing N* spectrum !! Potential impact of the complete experiments Sandorfi, Hoblit, Kamano, Lee arXiv:1010.0455 Fit to the existing data of 8 observables Fit to mock data of all 16 observables

  18. Previous model: Q2 < 1.5 GeV2 Dalitz plot of p2(2100)  ppp decay from our model New direction • Application of the DCC approach to meson physics: (3-body unitarity effect are fully taken into account) p g X B, D, J/Y... Exotic hybrids? f0, r, .. p p Heavy meson decays GlueX Summary and outlook • Fully combined analysis of pN, gN  pN, hN, KYreactions is underway. • Re-examine resonance poles • Analyze CLAS ep  epN data with Q2 < ~4 GeV2; extract N-N* e.m. transition f.f.s • Include pN, gN  ppN, wN, … reactions to the combined analysis. Nakamura, arXiv:1102.5753 Kamano, Nakamura, Lee, Sato, in preparation

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