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Meson spectroscopy with unitary coupled-channels model . Satoshi Nakamura Excited Baryon Analysis Center ( EBAC), JLab. Collaborators : H. Kamano (RCNP), T.-S.H. Lee (ANL), T. Sato (Osaka U). Why hadron spectroscopy ?. How. J PC , s pectrum, d ecay pattern key information - PowerPoint PPT Presentation
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Meson spectroscopy with unitary coupled-channels model
Satoshi Nakamura
Excited Baryon Analysis Center (EBAC), JLab
Collaborators : H. Kamano (RCNP), T.-S.H. Lee (ANL), T. Sato (Osaka U)
Why hadron spectroscopy ?
JPC , spectrum, decay pattern
key information
Quark-gluon dynamics (QCD) in non-perturbative regime
How
Partial wave analysis (PWA)
Data
Reliable analysis tool needed !
Analysis of three-meson productions
e.g., E852 (BNL) p p ppp p Chung et al., PRD 65, 072001 (2001)
isobar model * pp subsystem forms a resonance * 3rd p is a spectator
Question
Unitarity ?
Coupled-channels ?
3-body unitarity requires … Z-diagrams
Question to be addressed
How 3-body unitarity makes a difference in extracting hadron properties from data ?
Method 1. Construct a unitary and an isobar models
2. Fit them to the same Dalitz plot
3. Extract and compare M* properties from them
(pole position, coupling strength to decay channels)
pp model
Coupled-channels eq. for pp scattering (L , I )
Fitted to data
Coupling strength to decay channels
Unitary model
Isobar model
a1(1230) f0 p0 r p
Coupling strength to decay channels
W=1 GeV p2(1670) r p f2 p0
Unitary
Isobar
[degree]
W=1.66 GeV