Evidence for a new ${\Sigma }^{\ast }$ resonance with $J^P=1/2^{-}$ in the old data of $K^{-}p\to \Lambda {\pi }^{+}{\pi }^{-}$ reaction

Abstract

Distinctive patterns are predicted by quenched quark models and unquenched quark models for the lowest SU(3) baryon nonet with spin parity $J^P=1/2^{-}$. While the quenched quark models predict the lowest $1/2^{-}$ ${\Sigma }^{\ast }$ resonance to be above 1600 MeV, the unquenched quark models predict it to be around ${\Sigma }^{\ast }(1385)$ energy. Here we re-examine some old data of the $\text{kp}\to \text{la}$ reaction and find that besides the well established ${\Sigma }^{\ast }(1385)$ with $J^P=3/2^{+}$, there is indeed some evidence for the possible existence of a new ${\Sigma }^{\ast }$ resonance with $J^P=1/2^{-}$ around the same mass but with broader decay width. Higher statistic data on relevant reactions are needed to clarify the situation.

Comments: 7 pages, 4 figures