Review of the low-lying excited baryons $\hat{I}{\pounds }^{\ast }(1/2^{-})$

Abstract

Strong empirical and phenomenological indications exist for large sea-quark admixtures in the low-lying excited baryons. Investigating the low-lying excited baryon $\hat{I}{\pounds }^{\ast }(1/2^{-})$ is important to determine the nature of the low-lying excited baryons. We review the experimental and theoretical progress on the studies of the $\hat{I}{\pounds }^{\ast }(1/2^{-})$. Although several candidates have received intensive discussions, such as $\hat{I}\pounds (1620)$ and $\hat{I}\pounds (1480)$, their existence needs further confirmation. Following the prediction of the unquenched quark models for the $\hat{I}{\pounds }^{\ast }(1/2^{-})$, 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 $\hat{I}{\pounds }^{\ast }(1/2^{-})$ state.

9 pages, 2 figures, the version of publication in Chinese Physics Letters