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Hiroyuki Kamano Research Center for Nuclear Physics (RCNP) Osaka University

Dynamical Coupled-Channels Approach for Single- and Double-Pion Electroproductions : Status and Plans. Hiroyuki Kamano Research Center for Nuclear Physics (RCNP) Osaka University. EmNN *2012 Workshop @ USC, USA, August 13-15, 2012. Outline. 1. Background and motivation for N* spectroscopy

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Hiroyuki Kamano Research Center for Nuclear Physics (RCNP) Osaka University

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  1. Dynamical Coupled-Channels Approach for Single- and Double-Pion Electroproductions: Status and Plans Hiroyuki Kamano Research Center for Nuclear Physics (RCNP) Osaka University EmNN*2012 Workshop @ USC, USA, August 13-15, 2012

  2. Outline 1. Background and motivation for N* spectroscopy ANL-Osaka Dynamical Coupled-Channels (DCC) approach for N* spectroscopy 3. Status and plans for single- and double-pion electroproduction reactions 4. Related hadron physics program at J-PARC

  3. Background and motivation for N* spectroscopy(1 / 4)

  4. N* spectroscopy : Physics of broad & overlapping resonances N* : 1440, 1520, 1535, 1650, 1675, 1680, ... D : 1600, 1620, 1700, 1750, 1900, … Δ (1232) • Width: ~10 keVto ~10 MeV • Each resonance peak is clearly separated. • Width: a few hundred MeV. • Resonances are highly overlapping • in energy except D(1232).

  5. Hadron spectrum and reaction dynamics u meson cloud u d bare state • Various statichadron models have been proposed tocalculate • hadron spectrum and form factors. • In reality, excited hadrons are “unstable” and can exist • only as resonance states in hadron reactions. • Quark models, Bag models, Dyson-Schwinger approaches, Holographic QCD,… • Excited hadrons are treated as stable particles.The resulting masses are real. “molecule-like” states “Mass” becomes complex !! “pole mass” N* Constituent quark model core (bare state) + meson cloud What is the role of reaction dynamics in interpreting the hadron spectrum, structures, and dynamical origins ??

  6. ANL-Osaka Dynamical Coupled-Channels (DCC) approach forN* spectroscopy(2 / 4)

  7. ANL-Osaka Dynamical Coupled-Channels Approach for N* Spectroscopy “Dynamical coupled-channels model of meson production reactions” A. Matsuyama, T. Sato, T.-S.H. Lee Phys. Rep. 439 (2007) 193 • Objectives and goals: • Through the comprehensive analysis • of world dataof pN, gN, N(e,e’) reactions, • Determine N* spectrum (pole masses) • 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 Reaction Data Analysis Based on Reaction Theory Spectrum, structure,… of N* states Hadron Models Lattice QCD QCD

  8. Physical N*s will be a “mixture” of the two pictures: meson cloud core baryon meson Dynamical coupled-channels (DCC) model for meson production reactions For details see Matsuyama, Sato, Lee, Phys. Rep. 439,193 (2007) • Partial wave (LSJ) amplitudes of a  b reaction: • Reaction channels: • Transition Potentials: coupled-channels effect t-channel contact u-channel s-channel • Meson-Baryon Green functions p, r, s, w,.. Can be related to hadron states of the static hadron models (quark models, DSE, etc.) excluding meson-baryon continuum. N N, D Quasi 2-body channels Stable channels p D p Exchange potentials r,s N p N p N D D p D D r, s r, s Z-diagrams p p p p N N Bare N* states N*bare bare N* states Exchange potentials Z-diagrams

  9. DCC analysis (2006-2009) gN, pN, hN, pD, rN, sNcoupled-channels calculations were performed. Hadronic part • p N  pN : Analyzed to construct a hadronic part of the model up to W = 2 GeV Julia-Diaz, Lee, Matsuyama, Sato, PRC76 065201 (2007) • pN  h N : Analyzed to construct a hadronic part of the model up to W = 2 GeV Durand, Julia-Diaz, Lee, Saghai, Sato, PRC78 025204 (2008) • p N  pp N : Fully dynamical coupled-channels calculation up to W = 2 GeV Kamano, Julia-Diaz, Lee, Matsuyama, Sato, PRC79 025206 (2009) • g(*) N  p N : Analyzed to construct a E.M. part of the 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 : Fully dynamical coupled-channels calculation up to W = 1.5 GeV • Kamano, Julia-Diaz, Lee, Matsuyama, Sato, PRC80 065203 (2009) • Extraction of N* pole positions & new interpretation on the dynamical origin of P11 resonances • Suzuki, Julia-Diaz, Kamano, Lee, Matsuyama, Sato, PRL104 065203 (2010) • Stability and model dependence of P11 resonance poles extracted from pi N  pi N data • Kamano, Nakamura, Lee, Sato, PRC81 065207 (2010) • Extraction of gN  N* electromagnetic transition form factors Suzuki, Sato, Lee, PRC79 025205 (2009); PRC82 045206 (2010) Electromagnetic part Extraction of N* parameters

  10. pole A: pD unphys. sheet pole B: pD phys. sheet Dynamical origin ofnucleon resonances Suzuki, Julia-Diaz, Kamano, Lee, Matsuyama, Sato, PRL104 065203 (2010) Corresponds to hadron states from static hadron models Pole positions and dynamical origin of P11 resonances Double-pole nature of the Roper is found also from completely different approaches: Multi-channel reactions can generate many resonance poles from a single bare state !! Eden, Taylor, Phys. Rev. 133 B1575 (1964) For evidences in hadron and nuclear physics, see e.g., in Morgan and Pennington, PRL59 2818 (1987)

  11. Coupling to meson-baryon continuum states makes N* form factorscomplex !! N-N* transition form factors at resonance poles Extracted from analyzing the p(e,e’p)N data from CLAS Nucleon - 1st D13 e.m. transition form factors Fundamental nature of resonant particles (decaying states) Real part Imaginary part Julia-Diaz, Kamano, Lee, Matsuyama, Sato, Suzuki PRC80 025207 (2009) Suzuki, Sato, Lee, PRC82 045206 (2010)

  12. Dynamical coupled-channels (DCC) analysis Fully combinedanalysis of pN, gN N , hN , KL, KSreactions !! (more than 20,000 data points to fit) 2010 - 2012 8channels (gN,pN,hN,pD,rN,sN,KL,KS) < 2.1 GeV < 2 GeV < 2 GeV < 2 GeV < 2.2 GeV < 2.2 GeV 2006 - 2009 6channels (gN,pN,hN,pD,rN,sN) < 2 GeV < 1.6 GeV < 2 GeV ― ― ― • # of channels • p  N • gp N • phN • gphp • ppKL, KS • gpK+L, KS Kamano, Nakamura, Lee, Sato (2012)

  13. Partial wave amplitudes of pi N scattering Real part 8ch DCC-analysis (Kamano, Nakamura, Lee, Sato 2012) 6ch DCC-analysis (fitted to pN pN dataonly) [PRC76 065201 (2007)] Imaginary part

  14. Partial wave amplitudes of pi N scattering Real part 8ch DCC-analysis (Kamano, Nakamura, Lee, Sato 2012) 6ch DCC-analysis (fitted to pN pN dataonly) [PRC76 065201 (2007)] Imaginary part

  15. π- p  ηnreactions Kamano, Nakamura, Lee, Sato, 2012 • Analyzed data up to W = 2 GeV. • p- p  h n data are selected according to Durand et al. PRC78 025204.

  16. πN  KY reactions (1/2) Kamano, Nakamura, Lee, Sato, 2012 π-p  K0Σ0 π- p  K0Λ π+p  K+Σ+

  17. πN  KY reactions (2/2) Kamano, Nakamura, Lee, Sato, 2012 π- p  K0Λ π-p  K0Σ0 π+p  K+Σ+

  18. γp  πN reactions(1/2) γp π+n γp π0p Kamano, Nakamura, Lee, Sato, 2012

  19. γp  πN reactions(2/2) Kamano, Nakamura, Lee, Sato, 2012 γp π0p γp π+n

  20. γp  ηp reaction Kamano, Nakamura, Lee, Sato, 2012

  21. γp  K+Σ0, K0Σ+ reactions Kamano, Nakamura, Lee, Sato, 2012 γp K+Σ0 γp K0Σ+

  22. γp  K+Λreaction (1/4) Kamano, Nakamura, Lee, Sato, 2012

  23. γp  K+Λreaction (2/4) Kamano, Nakamura, Lee, Sato, 2012

  24. γp  K+Λreaction (3/4) Kamano, Nakamura, Lee, Sato, 2012

  25. γp  K+Λreaction (4/4) Kamano, Nakamura, Lee, Sato, 2012

  26. Status and plans for single- and double-pion electroproduction rections(3 / 4)

  27. Status and plans for analysis of electroproduction reactions 6-channel (2006-2009) 8-channel (2010-2012) (Q2 = 0 point) W < 1.6 GeV (the data analyzed) W < 2 GeV (the data analyzed) • γp πN • γp  ππN • ep  e’πN • ep e’ππN VERY preliminary resultsavailable W < 1.6 GeV (cross sections predicted) Not yet done (nonzero Q2) W < 1.6 GeV, Q2 < 1.5 (GeV/c)2 (the data analyzed) Not yet done Not yet done [Plan 2]: After Plan 1, we can give prediction for p(e,eππ)N cross sections. [Combined analysis of p(e,eπ)N and p(e,eππ)Nwill be a long term project.] [Plan 1]: After completing 8-ch analysis, immediately proceed to the analysis of CLAS p(e,eπ)N data and extract N-N* e.m. transition form factors up to Q2~ 4 (GeV/c)2.

  28. γp  ππN calculation with 8-ch. DCC model Prediction for γp ππ N total cross sections (not yet included in the fit) VERY PRELIMINARY !! 8-ch. DCC Full (Kamano, Nakamura, Lee, Sato 2012) 8-ch. DCC Nonresonant only 6-ch. DCC Full [PRC80 065203 (2010)] 6-ch. DCC Nonresonant only

  29. Related hadron physics program at J-PARC(4 / 4)

  30. Hadron physics program at J-PARC WG on “Hadron physics with high-momentum beam line at J-PARC” Currently J-PARC has high-momentumproton (< 30 GeV/c) and pion (~ 15 GeV/c) beams.  Now considered as one of the highest priority projects at KEK/J-PARC from April 2013. • Hadron properties in nuclear medium • pQCD, partonic structure of nucleon and nuclei • Charmed-hadron physics • Exotic hadrons and nuclei • N* physics (N*, Δ*, ...) • High-energy spin physics • Short-range NN correlations • Transition from hadron to quark degrees of freedom • Exclusive processes (GPD, quark counting, ...) • Quark/hadron interactions in nuclear medium (parton-energy loss, colortransparency) • J/ψ production mechanisms and its interactions in nuclear medium • Pion distribution amplitude, hadron-transition distribution amplitudes • Intrinsic charm and strange • … AND MORE TO COME!!

  31. Hadron physics program at J-PARC • Measurement of πN ππN & KY in high-mass N* region • (K. Hicks, K. Imai et al.) • πN ππN: “Critical missing piece” in N* spectroscopy. •  There is NO practical data that can be used for partial wave analysis • above W > 1.5 GeV. •  Above W > 1.5 GeV, πN ππNbecomes the dominant process of • the πN reactions. •  Most of the N*s decay dominantly to the ππN channel. The current N* mass spectrum might receive significant modifications and even new N* states might be discovered by the combined analysis including this new πN  ππN data !! The idea originates from “US-Japan Joint Workshop on Meson Production Reactions at Jefferson Lab and J-PARC” Hawaii, Oct. 2009.

  32. Hadron physics program at J-PARC • Measurement of forward p(π,ρ)X, p(π, K*)X reactions • (T. Ishikawa, T. Nakano et al.) high-p π K* (fast) ρ(fast) high-p π Q2 Q2 virtual π virtual K p p Y* (slow) N*, Δ* (slow) • Can access to Λ(1405) region • below KN threshold. • Could be used for extracting • strangeness changing axial • form factors. • Can be used for extracting • N-N* axial transition form factors Crucial for constructing reliable neutrino-nucleon/nucleus reaction models in resonance and DIS region.  Collaboration@J-PARC Branch of KEK Theory Center [Y. Hayato, M. Hirai, H. Kamano, S. Kumano, S. Nakamura, K. Saito, M. Sakuda, T. Sato] (http://j-parc-th.kek.jp/html/English/e-index.html)

  33. Summary Summary 2010 - 2012 8channels (gN,pN,hN,pD,rN,sN,KL,KS) < 2.1 GeV < 2 GeV < 2 GeV < 2 GeV < 2.2 GeV < 2.2 GeV ; 2006 - 2009 6channels (gN,pN,hN,pD,rN,sN) < 2 GeV < 1.6 GeV < 2 GeV ― ― ― • # of channels • p  N • gp N • phN • gphp • ppKL, KS • gpK+L, KS With the new 8-channels model, nucleon resonance parameters (mass spectrum, decay widths, etc.) are being investigated. (As presented in T. Sato’s talk) • After completing the combined analysis of πp, γp πN, ηN, KΛ, KΣ reactions, • immediately proceed to the analysis of CLAS p(e,eπ)N data and extract N-N* e.m. • transition form factors up to Q2 ~ 4 (GeV/c)2. • Combined analysis of p(e,eπ)N and p(e,eππ)N is considered as a long term project in future. • [Combined analysis of p(e,e’π)N, p(e,e’η)p, p(e,e’K)Y could be done quickly.]

  34. back up

  35. Phenomenological prescriptions of constructing conserved-current matrix elements As commonly done in practical calculations in nuclear and particle physics, currentlywe take a phenomenological prescription to construct conserved current matrix elements [T. Sato, T.-S. H. Lee, PRC60 055201 (2001)]: : Full e.m. current matrix elements obtained by solving DCC equations : photon momentum : an arbitrary four vector • A similar prescription is applied, e.g., in Kamalov and Yang, PRL83, 4494 (1999). • There are also other prescriptions that enable practical calculations satisfying • current conservation or WT identity: • Gross and Riska, PRC36, 1928 (1987) • Ohta, PRC40, 1335 (1989) • Haberzettl, Nakayama, and Krewald, PRC74, 045202 (2006).

  36. Experimental developments Since the late 90s, huge amount of high precision data of meson photo-production reactionson the nucleon target has been reported from electron/photon beam facilities. JLab, MAMI, ELSA, GRAAL, LEPS/SPring-8, … Opens a great opportunity to make quantitative study of the N* states !! E. Pasyuk’stalk at Hall-B/EBAC meeting

  37. N* states and PDG *s ? Most of the N*s wereextracted from ? ? ? Needcomprehensive analysisof ? Arndt, Briscoe, Strakovsky, Workman PRC 74 045205 (2006) channels !! From PDG 2010

  38. Width of N* resonances (Current status) Kamano, Nakamura, Lee, Sato, 2012 Note: Some freedom exists on the definition of partial width from the residue of the amplitudes.

  39. Spectrum of N* resonances (Current status) Real parts of N* pole values Ours PDG 4* PDG 3* L2I 2J Kamano, Nakamura, Lee, Sato, 2012

  40. Angular distribution Photon asymmetry 1334 MeV 1137 MeV 1232 MeV 1334 MeV 1137 MeV 1232 MeV 1462 MeV 1527 MeV 1617 MeV 1462 MeV 1527 MeV 1617 MeV 1729 MeV 1834 MeV 1958 MeV 1729 MeV 1834 MeV 1958 MeV γp  πN reactions 8ch DCC-analysis Kamano, Nakamura, Lee, Sato 2012 6ch DCC-analysis [PRC77 045205 (2008)] (fitted to gN pN data up to 1.6 GeV)

  41. Single pion electroproduction (Q2 > 0) Julia-Diaz, Kamano, Lee, Matsuyama, Sato, Suzuki, PRC80 025207 (2009) Fit to the structure function data (~ 20000) from CLAS p (e,e’ p0) p W < 1.6 GeV Q2 < 1.5 (GeV/c)2 is determined at each Q2. g q (q2 = -Q2) N N* N-N* e.m. transition form factor

  42. Single pion electroproduction (Q2 > 0) Julia-Diaz, Kamano, Lee, Matsuyama, Sato, Suzuki, PRC80 025207 (2009) Five-fold differential cross sections at Q2 = 0.4 (GeV/c)2 p (e,e’ p0) p p (e,e’ p+) n

  43. pi N  pi pi N reaction Kamano, Julia-Diaz, Lee, Matsuyama, Sato, PRC79 025206 (2009) Parameters used in the calculation are from pN  pN analysis. s (mb) W (GeV) Full result C. C. effect off Full result Phase space Data handled with the help of R. Arndt

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