N* analysis at

the Excited Baryon Analysis Center of JLab

Hiroyuki Kamano

(EBAC, Jefferson Lab)

CLAS12 2nd European Workshop, March 7-11, Paris, France

Objectives and goals:

Through the comprehensive analysis of world data of N, N, 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 for interpreting N* spectrum, structures and dynamical origins

Excited Baryon Analysis Center (EBAC) of Jefferson Lab

N* properties

QQCCDD

Lattice QCDHadron Models

Dynamical Coupled-Channels Analysis @ EBAC

Reaction Data

http://ebac-theory.jlab.org/Founded in January 2006

““Dynamical coupled-channels model of meson production reactions”Dynamical coupled-channels model of meson production reactions”

A. Matsuyama, T. Sato, T.-S.H. Lee Phys. Rep. 439 (2007) 193

Partial wave (LSJ) amplitude of a b reaction:

Reaction channels:

Transition potentials:

coupled-channels effect

Dynamical coupled-channels model

exchange potentialsof ground state

mesons and baryons

exchange potentialsof ground state

mesons and baryonsbare N* statesbare N* states

For details see Matsuyama, Sato, Lee, Phys. Rep. 439,193 (2007)

Strategy for N* study at EBAC

Stage 3Stage 3

Make a connection to hadron structure calculations; Explore the structure of the N* states.

Quark models, Dyson-Schwinger approaches, Holographic QCD,…

Stage 1Stage 1

Construct a reaction model through the comprehensive analysis of meson production reactions

Stage 2Stage 2

N* spectrum (poles); N* N, MB transition form factors (residues)

Confirm/reject N* with low-star status; Search for new N*

Extract resonance information from the constructed reaction model

Requires careful analytic continuation of amplitudes to complex energy plane Suzuki, Sato, Lee PRC79 025205; PRC82 045206

EBAC-DCC analysis (2006-2009)

N N : Used for constructing a hadronic model up to W = 2 GeV.Julia-Diaz, Lee, Matsuyama, Sato, PRC76 065201 (2007)

N N : Used for constructing a hadronic model up to W = 2 GeVDurand, Julia-Diaz, Lee, Saghai, Sato, PRC78 025204 (2008)

N N : First fully dynamical coupled-channels calculation up to W = 2 GeV.Kamano, Julia-Diaz, Lee, Matsuyama, Sato, PRC79 025206 (2009)

N 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)

N N : First fully dynamical coupled-channels calculation up to W = 1.5 GeV. Kamano, Julia-Diaz, Lee, Matsuyama, Sato, PRC80 065203 (2009)

Hadronic partHadronic part

Electromagnetic partElectromagnetic part

N, N, N (,N,N) coupled-channels calculations were performed.

N, N, N (,N,N) coupled-channels calculations were performed.

Dynamical coupled-channels effect on N* poles and form factors

Pole positions and dynamical origin of P11 resonancesPole positions and dynamical origin of P11 resonances

Suzuki, Julia-Diaz, Kamano, Lee, Matsuyama, Sato, PRL104 065203 (2010)Suzuki, Sato, Lee, PRC82 045206 (2010)

pole A: unphys. sheetpole B: 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 factorsNucleon - 1st D13 e.m. transition form factors

Real part Imaginary part

Crucial role of non-trivial multi-channel reaction

mechanisms for interpreting the structures and

dynamical origins of nucleon resonances !

EBAC-DCC analysis: 2010 ~

N N

N N

N N

N N

N KY

N K

2006 ~ 2009

5 channels (N,N,,N,N)

< 2 GeV

< 1.6 GeV

< 2 GeV

―

―

―

2010 ~

7 channels (N,N,,N,N,K,K)

< 2.1 GeV

< 2 GeV

< 2 GeV

< 2GeV

< 2.1 GeV

< 2.1 GeV

# of coupled channels

Fully combined analysis of N , N N , N , KY reactions !!

Pion-nucleon elastic scattering

Current model

(fully combined analysis, preliminarypreliminary)

Previous model (fitted to N N data only)[PRC76 065201 (2007)]

Target polarizationTarget polarization

1234 MeV1234 MeV

1449 MeV1449 MeV

1678 MeV1678 MeV

1900 MeV1900 MeV

Angular distribution Angular distribution

Single pion photoproduction

Current model (fully combined analysis, preliminarypreliminary)

Previous model (fitted to N N data up to 1.6 GeVup to 1.6 GeV) [PRC77 045205 (2008)]

Angular distribution Angular distribution Photon asymmetry Photon asymmetry

1137 MeV 1232 MeV

1334 MeV

1462 MeV 1527 MeV 1617 MeV

1729 MeV 1834 MeV 1958 MeV

1137 MeV 1232 MeV 1334 MeV

1462 MeV 1527 MeV 1617 MeV

1729 MeV 1834 MeV 1958 MeV

Preliminary!!Preliminary!!

1154 MeV 1232 MeV 1313 MeV

1416 MeV 1519 MeV 1617 MeV

1690 MeV 1798 MeV 1899 MeV

1154 MeV 1232 MeV 1313 MeV

1416 MeV 1519 MeV 1617 MeV

1690 MeV

1798 MeV 1899 MeV

1535 MeV

1674 MeV

1811 MeV

1930 MeV

1549 MeV

1657 MeV

1787 MeV

1896 MeV

Eta production reactions

Preliminary!!Preliminary!!

Analyzed data up to W = 2 GeV. p n data are selected following Durand et al. PRC78 025204.

Photon asymmetry

pi N KY reactions Preliminary!!Preliminary!!

Angular distribution Angular distribution Recoil polarizationRecoil polarization

1732 MeV

1845 MeV

1985 MeV

2031 MeV

1757 MeV

1879 MeV

1966 MeV

2059 MeV

1792 MeV

1879 MeV

1966 MeV

2059 MeV

1732 MeV

1845 MeV

1985 MeV

2031 MeV

1757 MeV

1879 MeV

1966 MeV

2059 MeV

1792 MeV

1879 MeV

1966 MeV

2059 MeV

gamma p K+ Lambda

Preliminary!!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 Observables of pseudoscalar photoproduction reactions

Take real and imaginary parts of amplitudes as parameters at each energy point

Monte Carlo sampling of L = 0 - 3 amplitudes (up to 107 per energy)

+ gradient minimization

Energy-independent multipole analysis of the existing p K+ data:

= Data available for p K+

Potential impact of the complete experiments

Sandorfi, Hoblit, Kamano, Lee arXiv:1010.0455

Bands of the best 300 multipole solutionsBands of the best 300 multipole solutions

Overall phase is fixed by setting E0+ real.

Wide solution bands with tightly clustered 2

Solutions are indistinguishable

within the existing data.

Real part

Imaginary part

0.05 0.03 0.10 0.08 0.18

Difference between Best and Largest 2

Difference between Best and Largest 2

E0+

M1+

To narrow the bands,

should increase statistics of the 8 observables ??

OR

should measure all the remaining polarization observables ??

Generate mock data with kinematics

and errors expected in the CLAS

experiments and repeat the analysis

W = 1900 MeV (Energy-independent fit to mock data)W = 1900 MeV (Energy-independent fit to mock data)

Sandorfi, Hoblit, Kamano, Lee arXiv:1010.0455

Potential impact of the complete experiments

2 / data = 0.6(best 2 solution)

2 / data = 1.4(largest 2

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 observablesFit to the existing data of 8 observables Fit to mock data of all 16 observablesFit 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 N, N N, N, KY reactions is underway.

Re-examine resonance poles

Analyze CLAS ep eN data with Q2 < ~4 GeV2; extract N-N* e.m. transition f.f.s

Include N, N N, N, … reactions to the combined analysis.

Previous model: Q2 < 1.5 GeV2

New directionNew direction

Application of the DCC approach to meson physics:

(3-body unitarity effect are fully taken into account)

Dalitz plot of 2(2100) decay

from our model

Dalitz plot of 2(2100) decay

from our model

f0, , ..

B, D, J/...

Heavy meson decays

p p

X Exotic hybrids?

GlueX

Nakamura, arXiv:1102.5753 Kamano, Nakamura, Lee, Sato, in preparation