Hyperon III: K-p-πΣ coupled-channel dynamics in the Λ(1405) mass region

• Published in: The European physical journal. A, Hadrons and nuclei Hadrons and nuclei, 2020, Vol.56 (5)
• Main Authors: Anisovich, A. V., Sarantsev, A. V., Nikonov, V. A., Burkert, V., Schumacher, R. A., Thoma, U., Klempt, E.
• Format: Article
• Language: English
• Subjects: Bubble chambers; Hadrons; Heavy Ions; Nuclear Fusion; Nuclear Physics; Particle and Nuclear Physics; Physics; Physics and Astronomy; Regular Article - Experimental Physics
• ISSN: 1434-6001; 1434-601X
• DOI: 10.1140/epja/s10050-020-00142-8

Low-energy data on the three charge states in γ p → K + ( Σ π ) from CLAS at JLab, on K - p → π 0 π 0 Λ and π 0 π 0 Σ from the Crystal Ball at BNL, bubble chamber data on K - p → π - π + π ± Σ ∓ , low-energy total cross sections on K - induced reactions, and data on the K - p atom are fitted with the BnGa partial-wave-analysis program. We find that the data can be fitted well with just one isoscalar spin-1/2 negative-parity pole, the Λ ( 1405 ) , and background contributions. In a fit with one isocsalar state, the Λ ( 1405 ) structure can be determined as a dominantly SU(3) singlet state. A fit with two isoscalar singlet states, with imposed properties of the low-mass state, is, however, also not incompatible with data.