Λ resonances studied in K ⁻ p → Σ ⁰ π ⁰ in a chiral quark model

Abstract

A chiral quark-model approach is extended to the study of the K̄N scattering at low energies. The process of K−p → Σ0π0 at PK ≳ 800 MeV/c (i.e. the center mass energy W ≳ 1.7 GeV) is investigated. The Λ(1405) S01 dominates the reactions over the energy region considered here. Around PK ≃ 400 MeV/c, the Λ(1520)D03 is responsible for a strong resonant peak in the cross section. Our analysis suggests that there exist configuration mixings within the Λ(1405) S01 and Λ(1670) S01 as admixtures of the [70,2 1, 1/2] and [70,2 8, 1/2] configurations. The Λ(1405) S01 is dominated by [70,2 1, 1/2], and Λ(1670) S01 by [70,2 8, 1/2]. The non-resonant background contributions, i.e. u-channel and t-channel, also play important roles in the explanation of the angular distributions due to amplitude interferences.