Review of the low-lying excited baryons ${\mathrm{\Sigma }}^{\ast }(1\mathrm{/}{2}^{-})$

Strong empirical and phenomenological indications exist for large sea-quark admixtures in the low-lying excited baryons. Investigating the low-lying excited baryon ${\mathrm{\Sigma }}^{\ast }(1\mathrm{/}{2}^{-})$ is important to determine the nature of the low-lying excited baryons. We review the experimental and theoretical progress on the studies of the ${\mathrm{\Sigma }}^{\ast }(1\mathrm{/}{2}^{-})$. Although several candidates have received intensive discussions, such as $\mathrm{\Sigma }(1620)$ and $\mathrm{\Sigma }(1480)$, their existence needs further confirmation. Following the prediction of the unquenched quark models for the ${\mathrm{\Sigma }}^{\ast }(1\mathrm{/}{2}^{-})$, many theoretical works suggested the existence of these states in various processes. Future experimental measurements could shed light on the existence of the low-lying excited ${\mathrm{\Sigma }}^{\ast }(1\mathrm{/}{2}^{-})$ state.