Identifying $\mathrm{\Sigma }(1380)$ and $\mathrm{\Sigma }(1430)$ in the $J\mathrm{/}\psi \to \mathrm{\Lambda }\pi \bar{\mathrm{\Sigma }}$ reaction

We study the $J\mathrm{/}\psi \to \mathrm{\Lambda }\pi \bar{\mathrm{\Sigma }}$ reaction by looking at the ${\pi }^{+}\mathrm{\Lambda }$ mass distribution at low energies, in search of signals for the low lying ${\mathrm{\Sigma }}^{+}$ states. Apart from a clear signal of the $\mathrm{\Sigma }(1385)(3\mathrm{/}{2}^{+})$ state, we find a smaller peak for the predicted $\mathrm{\Sigma }(1430)(1\mathrm{/}{2}^{-})$, which has already been confirmed by the Belle Collaboration. A first analysis, considering only the $\pi \mathrm{\Lambda }$ interaction, shows that the low energy part of the spectrum is better reproduced including contributions from the $\mathrm{\Sigma }(1430)$ and the predicted $\mathrm{\Sigma }(1380)(1\mathrm{/}{2}^{-})$ state that has been claimed before from analyses of different experiments. However, when we consider the $\pi \bar{\mathrm{\Sigma }}$ interaction the need for the $\mathrm{\Sigma }(1380)$ disappears.