1. Photoproduction of Λ*(1405)/Σ*(1385) at LEPS/SPring8
RCNP, Osaka University
DEUKSOON AHN
APSE2010

2. (using linearly polarized photon beam)
Physics Motivation
Λ(1405) : Meson-baryon resonance or 3-quark System ?
Σ(1385) with JP=3/2+ , I=1, and S=-1
Λ(1405) with JP=1/2- , I=0, and S=-1
~20 MeV I.
LEPS spectrometer +TPC
LEPS data, PRC78,035202(2008)M.Niiyama
g p K+ L(1405)  K+ S +p –
K+ S -p +
p K+ Σ(1385)  K+ L p 0
L*/S* = 0.54  ± 0.076
Strong Energy dependence!
II.
LEPS Forward angle
High Statistics !
To understand the production Mechanism,
- Differential Cross section
Photon Beam Asymmetry
(using linearly polarized photon beam)
p K+ L(1405) / Σ(1385)
: Using missing mass of K+
APSE2010

3. Photon Beam Asymmetry for Λ*(1405)and Σ*(1385)
Σ >0 ; Natural parity exchange
Σ <0 ; Unnatural parity exchange
Σ(1385) dominant
- K* exchange ?
Λ*(1405)
/Σ*(1385)
APSE2010