A possible $\hat{I}{\pounds }^{\ast }$ or $\hat{I}{›}^{\ast }$ resonance with $J^P=3/2^{-}$ in $K^{-}p\to K\hat{I}ž$ scattering

Abstract

We analyze the $K^{-}p\to K^{+}\hat{I}{ž}^{-}$ and $K^{-}p\to K^0\hat{I}{ž}^0$ processes in the energy region $1.8<\sqrt{s}<2.8$ GeV within an effective Lagrangian approach. The $\hat{I}›(1800)$ and $\hat{I}\pounds (2250)$ resonances, along with the ground states $\hat{I}\pounds$ and $\hat{I}›$, are included. Additionally, a possible $J^P=3/2^{-}$ $\hat{I}{\pounds }^{\ast }$ or $\hat{I}{›}^{\ast }$ resonance with a mass around 1.9 GeV and a width of approximately 200 MeV is introduced to describe the structure at 2.0 GeV in the total cross section and reproducing the threshold behavior. The two possible solutions corresponding to $\hat{I}{\pounds }^{\ast }(3/2^{-})$ and $\hat{I}{›}^{\ast }(3/2^{-})$ cannot be distinguished by the existing data. Predictions for the polarization of the final-state $\hat{I}ž$ and the cross section of $K^{-}n\to K^0\hat{I}{ž}^{-}$ are compared with the experimental data, we find that the results of solution-II with $\hat{I}{›}^{\ast }(3/2^{-})$ are much better. We also discuss the possible interpretations of the introduced $3/2^{-}$ hyperon as a pentaquark candidate, e.g. an $S$-wave $K\hat{I}ž(1530)$ hadronic molecule. However, since the polarization data suffer from rather large uncertainties, more data inputs are needed in future experiments, for example, J-PARC, HIAF and JLab.

21 pages, 7 figures