Possible $\Sigma^*(1/2^-)$ in the initial-state polarized $\gamma N\rightarrow K^{+} \Sigma^*(1385) \rightarrow K^{+} \pi \Lambda$ reaction near threshold

TL;DR

This study uses an effective Lagrangian approach to explore the potential existence of a new $\Sigma^*(1/2^-)$ state near 1380 MeV in a polarized photon-induced reaction, predicting measurable differences in cross sections and angular distributions.

Contribution

It introduces a theoretical analysis of a proposed $\Sigma^*(1/2^-)$ state and predicts observable effects that can confirm its existence in future experiments.

Findings

Distinct differences in helicity cross sections depending on the $\Sigma^*(1/2^-)$ existence

Predicted angular distribution variations in the $\pi ext{--}\Lambda$ system

Theoretical framework guiding future experimental searches

Abstract

By using an effective Lagrangian method, we study the effects of a newly proposed $\Sigma^*(1/2^-)$ state with mass around 1380 MeV in the initial-state polarized $\gamma N\rightarrow K^{+} \Sigma^*(1385) \rightarrow K^{+} \pi \Lambda$ process near threshold. The theoretical predictions for the helicity cross sections $\sigma_{3/2}$, $\sigma_{1/2}$ as well as their ratios, and the angular distributions of $\pi$ in the $\pi\Lambda$ center-of-mass system are given. It is found that assuming $\Sigma^*(1/2^-)$ exists or not, these physical quantities are distinctly different. So our results could be useful for the investigation of the existence of $\Sigma^*(1/2^-)$ when the experimental data are available in the future.