Extraction of nucleon resonances from global analysis of
Extraction of nucleon resonances from global analysis of meson production reactions at EBAC Hiroyuki Kamano (Excited Baryon Analysis Center, Jefferson Lab) In collaboration with B. Julia-Diaz, T. -S. H. Lee, A. Matsuyama, S. Nakamura, T. Sato, N. Suzuki BARYONS’ 10, December 7 th – 11 th, Osaka, Japan
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 data of N, g. N, N(e, e’) reactions, Dynamical Coupled-Channels Analysis @ EBAC ü Determine N* spectrum (pole positions) ü meson Extractproduction N* form factors N* coupled-channels properties “Dynamical model of reactions” (e. g. , N-N* e. m. transition form factors) A. Matsuyama, T. Sato, T. -S. H. Lee Phys. Rep. 439 (2007) 193 Hadron Models Lattice QCD Q CD ü Provide reaction mechanism information necessary for interpreting N* properties, structures and dynamical origins
Dynamical coupled-channels model of EBAC (EBAC-DCC model) For details see Matsuyama, Sato, Lee, Phys. Rep. 439, 193 (2007) ü Partial wave (LSJ) amplitude of a b reaction: Physical N*s will be a “superposition” of the two pictures: baryon coupled-channels effect meson cloud ü Reaction channels: core meson ü Transition potentials: exchange potentials of ground state mesons and baryons bare N* states
Strategy for N* study at EBAC Stage 1 Construct a reaction model through the comprehensive analysis of meson production reactions Requires careful analytic continuation of amplitudes to complex energy plane Stage 2 Suzuki, Sato, Lee PRC 79 025205; PRC 82 045206 Extract resonance information from the constructed reaction model Ø N* pole positions; N* g. N, MB transition form factors Ø 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. Ø Quark models, DSE, Large Nc, Holographic QCD, …
EBAC-DCC analysis (2006 -2009) Hadronic part ü N N N, h. N, N ( D, r. N, s. N) coupledchannels calculations were performed. : Used for constructing a hadronic model up to W = 2 Ge. V. Julia-Diaz, Lee, Matsuyama, Sato, PRC 76 065201 (2007) ü N h. N : Used for constructing a hadronic model up to W = 2 Ge. V Electromagnetic part Durand, Julia-Diaz, Lee, Saghai, Sato, PRC 78 025204 (2008) ü N N : First full dynamical coupled-channels calculation up to W = 2 Ge. V. Kamano, Julia-Diaz, Lee, Matsuyama, Sato, PRC 79 025206 (2009) ü g(*) N N : Used for constructing a E. M. model up to W = 1. 6 Ge. V and Q 2 = 1. 5 Ge. V 2 (photoproduction) Julia-Diaz, Lee, Matsuyama, Sato, Smith, PRC 77 045205 (2008) (electroproduction) Julia-Diaz, Kamano, Lee, Matsuyama, Sato, Suzuki, PRC 80 025207 (2009) ü g N N : First full dynamical coupled-channels calculation up to W = 1. 5 Ge. V. Kamano, Julia-Diaz, Lee, Matsuyama, Sato, PRC 80 065203 (2009)
Dynamical coupled-channels effect on N* poles and form factors Suzuki, Julia-Diaz, Kamano, Lee, Matsuyama, Sato, PRL 104 065203 (2010) Suzuki, Sato, Lee, PRC 82 045206 (2010) Dynamical origin of P 11 resonances N-1 st D 13 e. m. transition form factor Re(Dressed vertex) Im(Dressed vertex) Bare vertex (Real) Critical role of non-trivial multi-channel reaction mechanisms for interpreting the structure and dynamical origin of nucleon resonances !!
EBAC-DCC analysis: 2010 ~ Full-combined analysis of g. N , N N , h. N , KY reactions !! 2006 ~ 2009 2010 ~ 5 channels ( N, h. N, D, r. N, s. N) 7 channels ( N, h. N, D, r. N, s. N, KL, KS) ü N N < 2 Ge. V ü g. N N < 1. 6 Ge. V < 2 Ge. V ü N h. N < 2 Ge. V ü g. N h. N ― < 2 Ge. V ü N KY ― < 2. 1 Ge. V ü g. N KL ― < 2. 1 Ge. V ü # of coupled channels
Pion-nucleon elastic scattering Angular distribution Target polarization 1234 Me. V 1449 Me. V 1678 Me. V 1900 Me. V Current model (full combined analysis, PRELIMINARY) Previous model (fitted to N N data only) [PRC 76 065201 (2007)]
Single pion photoproduction Preliminary!! Angular distribution 1154 Me. V 1232 Me. V 1137 Me. V 1232 Me. V 1416 Me. V 1462 1519 Me. V 1527 1690 Me. V 1729 1798 Me. V 1834 Photon asymmetry 1313 Me. V 1334 1154 Me. V 1137 Me. V 1232 Me. V 1313 Me. V 1334 Me. V 1416 Me. V 1462 1527 Me. V 1519 1617 Me. V 1834 1798 Me. V 1958 1899 Me. V 1617 1958 1899 Me. V 1690 Me. V 1729 Me. V Current model (full combined analysis, preliminary) Previous model (fitted to g. N N data up to 1. 6 Ge. V) [PRC 77 045205 (2008)]
Eta production reactions Preliminary!! Photon asymmetry 1535 Me. V 1549 Me. V 1674 Me. V 1657 Me. V 1811 Me. V 1787 Me. V 1930 Me. V ü Analyzed data up to W = 2 Ge. V. ü - p h n data are selected following Durand et al. PRC 78 025204. 1896 Me. V
pi N KY reactions Preliminary!! Angular distribution 1732 Me. V 1757 Me. V Recoil polarization 1792 Me. V 1732 Me. V 1792 Me. V 1757 Me. V 1845 Me. V 1985 Me. V 2031 Me. V 1879 Me. V 1966 Me. V 2059 Me. V 1879 Me. V 1845 Me. V 1879 Me. V 1985 Me. V 1966 Me. V 2031 Me. V 2059 Me. V 1966 Me. V 2059 Me. V
gamma p K+ Lambda Formulae for calculating polarization observables Sandorfi, Hoblit, Kamano, Lee ar. Xiv: 1010. 0455 1781 Me. V Preliminary!! 1883 Me. V 2041 Me. V Measure ALL 15 polarization observables !! “Over-complete experiment” is planned by CLAS@JLab ! Expected to be a critical source for discovering new N* states !!
Summary and outlook ü Full-combined analysis of N, g. N N, h. N, KY reactions is underway. Ø Re-examine resonance poles Previous model: Q 2 < 1. 5 Ge. V 2 Ø Analyze CLAS ep e N data with Q 2 < 6 Ge. V 2; extract N-N* e. m. transition f. f. s Ø Include N, g. N N, w. N, … reactions to the combined analysis. New direction (Presented by S. Nakamura at SP 01 session) ü Application of the EBAC-DCC approach to meson physics: (3 -body unitarity effects are fully taken into account) B, D, J/Y. . . f 0, r, . . Heavy meson decays g p X Exotic hybrids? p Glue. X experiment @ Hall D of JLab
Back up
Dynamical origin of P 11 resonances Suzuki, Julia-Diaz, Kamano, Lee, Matsuyama, Sato, PRL 104 042302 (2010) Pole trajectory of N* propagator self-energy: Bare state Im E (Me. V) h. N threshold (h. N, r. N, D) = (p, u, u) D threshold (h. N, r. N, D) = (p, u, -) A: 1357– 76 i r. N threshold (h. N, r. N, D) = (p, u, p) (h. N, r. N, D) = (u, u, u) B: 1364– 105 i C: 1820– 248 i ( N, s. N) = (u, p) for three P 11 poles Re E (Me. V)
pi N pi pi N reaction Kamano, Julia-Diaz, Lee, Matsuyama, Sato, PRC 79 025206 (2009) Parameters used in the calculation are from N N analysis. Full result C. C. effect off Full result Phase space Data handled with the help of R. Arndt
EBAC-DCC analysis (2006 -2009) Full c. c. effect of N( D, r. N, s. N) & h. N off Full c. c effect off Coupled-channels effect in various reactions Full c. c. effect of N( D, r. N, s. N) & h. N off
N* states and PDG *s Arndt, Briscoe, Strakovsky, Workman PRC 74 045205 (2006) ? ? Most of the N*s were extracted from ? ? Need comprehensive analysis of ? channels !!
“Priority” of coupled-channels effect g. N (also N) reaction cross sections in the resonance region are dominated by N and N final states. At least, the couplings of N and N channels should be taken into account in the analyses of any g. N ( N) MB reactions. Figure: E. Pasyuk’s talk at Hall-B/EBAC meeting
“Complete Experiment” of pseudoscalar meson photoproduction reactions Measure ALL polarization observables needed “Complete Experiment” = to determine amplitudes up to overall phase unpolarized diff. crs. sec. 8 /16 observables needed! Chiang, Tabakin PRC 55 2054 (1997) single spin ü Measurement of g. N KY pol. obs. is very active. beam-target ü OVER-complete experiments planned by CLAS for g p K+ L, g n KY. beam-recoil target-recoil Provides critical information on N* KY decays !! Much room for new N* state searches
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