Transcript PPT
N* analysis at the Excited Baryon Analysis Center of JLab Hiroyuki Kamano (EBAC, Jefferson Lab) CLAS12 2nd European Workshop, March 7-11, Paris, France 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 pN, gN, N(e,e’) reactions, Dynamical Coupled-Channels Analysis @ EBAC Determine N* spectrum (pole positions) 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 QCD Provide reaction mechanism information necessary for interpreting N* spectrum, structures and dynamical origins Dynamical coupled-channels model For details see Matsuyama, Sato, Lee, Phys. Rep. 439,193 (2007) Partial wave (LSJ) amplitude of a b reaction: coupled-channels effect Reaction channels: 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 Suzuki, Sato, Lee PRC79 025205; PRC82 045206 Stage 2 Extract resonance information from 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,… EBAC-DCC analysis (2006-2009) pN, hN, ppN (pD,rN,sN) coupledchannels calculations were performed. Hadronic part pNpN : Used for constructing a hadronic model up to W = 2 GeV. Julia-Diaz, Lee, Matsuyama, Sato, PRC76 065201 (2007) pNhN : Used for constructing a hadronic model up to W = 2 GeV Durand, Julia-Diaz, Lee, Saghai, Sato, PRC78 025204 (2008) p N p p N : First fully dynamical coupled-channels calculation up to W = 2 GeV. Kamano, Julia-Diaz, Lee, Matsuyama, Sato, PRC79 025206 (2009) Electromagnetic part 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 p p N : First fully dynamical coupled-channels calculation up to W = 1.5 GeV. Kamano, Julia-Diaz, Lee, Matsuyama, Sato, PRC80 065203 (2009) 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 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) Nucleon - 1st D13 e.m. transition form factors Crucial role of non-trivial multi-channel reaction mechanisms for interpreting the structures and dynamical origins of nucleon resonances ! Real part Imaginary part EBAC-DCC analysis: 2010 ~ Fully combined analysis of gN , pN pN , hN , KY reactions !! 2006 ~ 2009 2010 ~ 5 channels 7 channels (pN,hN,pD,rN,sN) (pN,hN,pD,rN,sN,KL,KS) pN pN < 2 GeV < 2.1 GeV gN pN < 1.6 GeV < 2 GeV pN hN < 2 GeV < 2 GeV gN hN ― < 2GeV pN KY ― < 2.1 GeV gN KL ― < 2.1 GeV # of coupled channels 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 data only) [PRC76 065201 (2007)] Single pion photoproduction Preliminary!! Angular distribution 1154 MeV 1232 MeV 1137 MeV 1232 MeV 1416MeV MeV 1462 1519MeV MeV 1527 1729 1690MeV MeV 1834 1798MeV MeV Photon asymmetry 1313 MeV MeV 1334 1154 MeV 1137 MeV 1232 MeV 1232 MeV 1313 MeV 1334 MeV 1416MeV MeV 1462 1527 MeV 1519 1617 1617 MeV MeV 1834 1798MeV MeV 1958 1899MeV MeV 1617 MeV MeV 1617 1958 1899 MeV MeV 1690 MeV 1729 MeV Current model (fully combined analysis, preliminary) Previous model (fitted to gN pN data up to 1.6 GeV) [PRC77 045205 (2008)] Eta production reactions Photon asymmetry 1535 MeV 1549 MeV 1674 MeV 1657 MeV Preliminary!! 1811 MeV 1787 MeV 1930 MeV Analyzed data up to W = 2 GeV. p- p h n data are selected following Durand et al. PRC78 025204. 1896 MeV pi N KY reactions Preliminary!! Angular distribution 1732 MeV 1757 MeV Recoil polarization 1792 MeV 1732 MeV 1792 MeV 1757 MeV 1845 MeV 1985 MeV 2031 MeV 1879 MeV 1966 MeV 2059 MeV 1879 MeV 1845 MeV 1879 MeV 1879 MeV 1985 MeV 1966 MeV 1966 MeV 2031 MeV 2059 MeV 2059 MeV 1966 MeV 2059 MeV gamma p K+ Lambda Preliminary!! 1781 MeV 1883 MeV 2041 MeV Potential impact of the complete experiments Sandorfi, Hoblit, Kamano, Lee arXiv:1010.0455 Observables of pseudoscalar photoproduction reactions Energy-independent multipole analysis of the existing gp K+ L data: Take real and imaginary parts of amplitudes as parameters at each energy point = Data available for gp K+L Monte Carlo sampling of L = 0 - 3 amplitudes (up to 107 per energy) + gradient minimization Potential impact of the complete experiments Sandorfi, Hoblit, Kamano, Lee arXiv:1010.0455 Bands of the best 300 multipole solutions E0+ Real part To narrow the bands, Generate mock data with 0.05 0.03 0.10 0.08 kinematics 0.18 and errors expected in the CLAS Difference between Best should increase statistics of the 8 observables ?? the analysis experiments and repeat 2 and Largest c M1+ OR Overall phase is fixed by setting E0+ real. should measure all the remaining polarization observables ?? Imaginary part Wide solution bands with tightly clustered c2 Solutions are indistinguishable within the existing data. 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.] 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 “Complete experiments” at CLAS A crucial source for determining amplitudes and establishing N* spectrum !! Summary and outlook Fully combined analysis of pN, gN pN, hN, KY reactions is underway. Re-examine resonance poles Previous model: Q2 < 1.5 GeV2 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. New direction Nakamura, arXiv:1102.5753 Kamano, Nakamura, Lee, Sato, in preparation Application of the DCC approach to meson physics: (3-body unitarity effect are fully taken into account) p B, D, J/Y... g X Exotic hybrids? f0, r, .. Heavy meson decays p p GlueX Dalitz plot of p2(2100) ppp decay from our model