The Theoretical Study of $\pi^+p\to pa_0^+\phi$ Reaction

TL;DR

This paper presents a theoretical analysis of the $ pi^+p o pa_0^+$ reaction, predicting cross sections and exploring the role of $ Delta(1940)$ and $ Delta(1920)$ resonances, aiding future experimental investigations.

Contribution

It introduces a model including $ Delta(1940)$ and $ Delta(1920)$ resonances with $ ho$ and $p$ exchange, providing predictions for cross sections and resonance contributions.

Findings

$ Delta(1940)$ significantly influences near-threshold production.

The model predicts total and differential cross sections.

$ Delta(1940)$ coupling to $pa_0$ is crucial for understanding the reaction.

Abstract

We study the production of hyperon resonances in the $\pi^+p\to pa_0^+\phi$ reaction within an effective Lagrangian approach. The model includes the production of $\Delta(1940)$ and $\Delta(1920)$ in the intermediate state excited by the $\rho$ and $p$ exchanges between the initial proton and $\pi$ meson. Due to the large contribution of $\rho$ exchange in $\Delta(1940)$ production, $\Delta(1940)$ is found a significant contribution near the threshold in this reaction. We provide total and differential cross section predictions for the reation and discuss the possible influence of model parameters, off-shell effects and branching ratios for $\Delta(1940)\to pa_0$ and $\Delta(1920)\to pa_0$ decays, which will be useful in future experimental studies. This reaction can provide a platform for studying the features of $\Delta(1940)$ resonance, especially the coupling to $pa_0$ channel.