Role of five-quark components in radiative and strong decays of the Lambda(1405) resonance

TL;DR

This study investigates the internal five-quark structure of the Lambda(1405) resonance using an extended chiral quark model, revealing significant five-quark contributions to its decay processes and matching experimental decay widths.

Contribution

It introduces a detailed analysis of five-quark components in Lambda(1405) and their impact on decay amplitudes, highlighting the importance of configuration mixing and quark component transitions.

Findings

50% five-quark admixture reproduces experimental decay width

Configuration mixing significantly affects decay amplitudes

Transitions between three- and five-quark states are substantial

Abstract

Within an extended chiral constituent quark model, three- and five-quark structure of the $S_{01}$ resonance $\Lambda(1405)$ is investigated. Helicity amplitudes for the electromagnetic decays ($\Lambda(1405) \to \Lambda(1116)\gamma$, $\Sigma(1194)\gamma$), and transition amplitudes for strong decays ($\Lambda(1405)\to\Sigma(1194)\pi$, $ K^{-}p$) are drived, as well as the relevant decay widths. The experimental value for the strong decay width, $\Gamma_{\Lambda(1405)\to (\Sigma \pi)^\circ}=50\pm 2$ MeV, is well reproduced with about 50% of five-quark admixture in the $\Lambda(1405)$. Important effects due to the configuration mixings among $\Lambda^{2}_{1}P_{A}$, $\Lambda^{2}_{8}P_{M}$ and $\Lambda^{4}_{8}P_{M}$ are found. In addition, transitions between the three- and five-quark components in the baryons turn out to be significant in both radiative and strong decays of the $\Lambda(1405)$ resonance.