Possible $Σ({1\over2}^-)$ under the $Σ^*(1385)$ peak in $KΣ^*$ photoproduction

The LEPS collaboration has recently reported a measurement of the reaction $γn\to K^+Σ^{*-}(1385)$ with linearly polarized photon beam at resonance region. The observed beam asymmetry is sizably negative at $E_γ=1.8-2.4 \mathrm{GeV}$, in contrast to the presented theoretical prediction. In this paper, we calculate this process in the framework of the effective Lagrangian approach. By including a newly proposed $Σ(J^P={1\over2}^-)$ state with mass around 1380~MeV, the experimental data for both $γn$ and $γp$ experiments can be well reproduced. It is found that the $Σ({1\over2}^-)$ and/or the contact term may play important role and deserve further investigation.

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