Mechanism of $K^- p \to \eta\Lambda$ reaction near threshold

TL;DR

This paper investigates the $K^- p o \eta\Lambda$ reaction near threshold using an effective Lagrangian approach, proposing a new $D_{03}$ resonance to explain experimental data and suggesting further experimental verification.

Contribution

It introduces a new $D_{03}$ resonance with specific properties to explain the reaction mechanism near threshold, supported by analysis of experimental data.

Findings

Identification of a new $D_{03}$ resonance at 1668.5 MeV

Resonance width estimated at 1.5 MeV

Reaction $par p o \Lambdaar \Lambda \eta$ is promising for further searches

Abstract

Within an effective Lagrangian approach, we investigate the reaction mechanism of $K^- p\to \eta\Lambda$ near threshold. It is found that a new $D_{03}$ resonance, with mass $M=1668.5\pm 0.5$MeV and width $\Gamma=1.5\pm0.5$MeV, is needed to interpret the experimental data reported by the Crystal Ball collaboration. To verify our results, remeasurements on the differential cross sections and $\Lambda$ polarization in this reaction will be helpful. Furthermore, we also show that the reaction $p\bar p\to \Lambda\bar \Lambda \eta$ is a good place to look for this new resonance if it exists.