PNU

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Motivation Formalism Results Summary
PNU NuRI
A new nucleon resonance
in eta photoproduction
Ki-Seok Choi1, Seung-Il Nam2, Atsushi Hosaka3, Hyun-Chul Kim1
1.Nuclear physics Radiation technology
Institute (NuRI), Pusan National Univ.,
Korea 2. Yukawa Institute for Theoretical Physics
(YITP), Kyoto Univ., Japan 3.Research Center for
Nuclear Physics (RCNP), Osaka Univ., Japan
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Motivation Formalism Results Summary
PNU NuRI

Motivation
GRAALhep-ex/0409032
Only for the neutron
Peak appears at 1675MeV
Width 10MeV
(with Fermi motion correction)
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Motivation Formalism Results Summary
PNU NuRI

Other results
Peak structure exists!
hep-ex/0703003
Tohoku LNS result
GRAAL recent result
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Motivation Formalism Results Summary
PNU NuRI

Results of spin 1/2
k.s.choi et al., Phys.lett.B636,253
No evidence of spin 1/2 for N(1675). Check other
physical observables.
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Motivation Formalism Results Summary
PNU NuRI

How to describe?
in region of 1.4GeV2.0GeV
Resonance of
Jp1/2 and 3/2
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Motivation Formalism Results Summary
PNU NuRI

Interections for backgrounds
Coupling constant set
V.G.J.Stoks and T.A.Rijken,Phys.Rev.C 59, 3009
(1999)
L.Tiator, C.Bennhold and S.S.Kamalov, Nucl.Phys.A
580, 455 (1994)
From partial decay width
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Motivation Formalism Results Summary
PNU NuRI

Interections for resonance
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Motivation Formalism Results Summary
PNU NuRI

Spinors for higher spin
Spin3/2
Spin5/2
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Motivation Formalism Results Summary
PNU NuRI

couplings for resonance
A.I.Titov and T.-S.H.Lee Phys. Rev. c66, 015204
(2002).
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Motivation Formalism Results Summary
PNU NuRI

Amplitudes for backgrounds
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Motivation Formalism Results Summary
PNU NuRI

Amplitudes for resonance
The projection operators for higher spin
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Motivation Formalism Results Summary
PNU NuRI


Parameters for calculation
Parameters of the nucleon resonance
Cut off parameter
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Motivation Formalism Results Summary
PNU NuRI

Numerical calculation
The physical observable involved N(1675)
resonance for Jp1/2 and 3/2
Differential cross section VS. energy in 140
Beam asymmetry in 140
strangth of transition magnetic moment of N(1675)
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Motivation Formalism Results Summary
PNU NuRI

Differential crossection(1)
Neutron case
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Motivation Formalism Results Summary
PNU NuRI

Differential crossection(2)
Proton case
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Motivation Formalism Results Summary
PNU NuRI

Beam asymmetry(1)
Neutron case
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Motivation Formalism Results Summary
PNU NuRI

Beam asymmetry(2)
Proton case
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Motivation Formalism Results Summary
PNU NuRI

Numerical results
The physical observable involved N(1675)
resonance for Jp1/2 and 3/2
Differential cross section VS. energy in 140
proton and neutron channels are described
successfully .
Beam asymmetry in 140
Neutron case good proton case not as good
as neutron
strength of transition magnetic moment of N(1675)
Spin 1/2 case around 0.1 spin 3/2 case
around 0.010.03.
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Motivation Formalism Results Summary
PNU NuRI

Summary and conclusion
The Born approximation and effective Lagrangian
method.
reproduction The GRAAL experiment with seven
resonances (N(1520),N(1535),N(1675),
N(1520), N(1710),N(1720)N(1675)new )
Successful description of physical observations
for neutron case.
Comparison between spin 1/2 and spin 3/2 results