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

Abstract

Within an extended chiral constituent quark model, three- and five-quark structure of the $S_{01}$ resonance $Λ(1405)$ is investigated. Helicity amplitudes for the electromagnetic decays ($Λ(1405) \to Λ(1116)γ$, $Σ(1194)γ$), and transition amplitudes for strong decays ($Λ(1405)\toΣ(1194)π$, $ K^{-}p$) are drived, as well as the relevant decay widths. The experimental value for the strong decay width, $Γ_{Λ(1405)\to (Σπ)^\circ}=50\pm 2$ MeV, is well reproduced with about 50% of five-quark admixture in the $Λ(1405)$. Important effects due to the configuration mixings among $Λ^{2}_{1}P_{A}$, $Λ^{2}_{8}P_{M}$ and $Λ^{4}_{8}P_{M}$ 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 $Λ(1405)$ resonance.

typos and numerical mistakes corrected, to appear in Phys. Rev. C