Further evidence for the $Σ^{*}$ resonance with $J^P=1/2^-$ around 1380 MeV

Abstract

The unquenched quark models predict the new particle $Σ^*$ with spin parity $J^P=1/2^-$ and its mass is around the well established $Σ^*(1385)$ with $J^P=3/2^+$. Here by using the effective Lagrangian approach we study \kp\ reaction at the range of $Λ^{*}(1520)$ peak, comparing the resulting total cross section, and $π^+π^-$, $Λπ^+$, $Λπ^-$ invariant squared mass distributions for various incident $K^-$ momenta, as well as the production angular distribution of the $Λ$ with the data from the Lawrence Berkeley Laboratory 25-inch hydrogen bubble chamber, we find that, apart from the existing resonance $Σ^{*}(1385)$ with $J^P=3/2^+$, there is a strong evidence for the existence of the new resonance $Σ^{*}$ with $J^P=1/2^-$ around 1380 MeV. Higher statistic data on relevant reactions are needed to clarify the situation.