Photoproduction of $\Lambda $(1405) and $\Sigma ^{0}$(1385) on the proton at E$\gamma $=1.5 - 3.0 GeV at SPring-8/LEPS

The $\Lambda $(1405) is assigned as a p-wave q3 baryon in a quark model. However, it is also suggested that $\Lambda $(1405) has a non-q3 structure such as a meson-baryon molecular state. On the other hand, $\Sigma ^{0}$(1385) is firmly established as a q3 state baryon. The difference of the internal structure of $\Lambda $(1405) and $\Sigma ^{0}$(1385) may appear in the photoproduction cross sections and/or photon beam asymmetries of these two hyperons. Recently, differential cross sections for $\gamma $p $\to $ K$^{+}\Lambda $(1405) and $\gamma $p $\to $ K$^{+}\Sigma ^{0}$(1385) reactions were measured by LEPS collaboration. However, the statistics were limited because the contribution of free protons in the CH$_{2}$ target was extracted by subtracting carbon contributions which were dominant. A new experiment was carried out with liquid hydrogen target and linearly polarized photon beam. In order to detect decay products of hadrons, a time projection chamber surrounding the liquid target was used together with the LEPS spectrometer. The integrated luminosity is about 3 times larger than that of the previous experiment in the photon energy range E$\gamma $=1.5 - 2.4 GeV. In addition, we can access higher photon energy region because the maximum E$\gamma $ of 2.97 GeV was achieved. The more detailed information of differential cross sections of $\gamma $p $\to $ K$^{+}\Lambda $(1405) and $\gamma $p $\to $ K$^{+}\Sigma ^{0}$(1385) and line shapes of $\Lambda $(1405) will be obtained from new data. The photon beam asymmetry will be also investigated.