Hyperon III: coupled-channel dynamics in the mass region

A. V. Anisovich; A. V. Sarantsev; V. A. Nikonov; V. Burkert; R. A. Schumacher; U. Thoma; E. Klempt

doi:10.1140/epja/s10050-020-00142-8

EPJ

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2023 Impact factor 2.6

Hadrons and Nuclei

Open Access

Eur. Phys. J. A (2020) 56: 139
https://doi.org/10.1140/epja/s10050-020-00142-8

Regular Article - Experimental Physics

Hyperon III: $K^{-}p - \pi \varSigma$ coupled-channel dynamics in the $\varLambda (1405)$ mass region

A. V. Anisovich¹^,2, A. V. Sarantsev¹^,2, V. A. Nikonov¹^,2, V. Burkert³, R. A. Schumacher⁴, U. Thoma¹ and E. Klempt¹^*

¹ Helmholtz–Institut für Strahlen–und Kernphysik, Universität Bonn, 53115, Bonn, Germany
² National Research Centre “Kurchatov Institute”, Petersburg Nuclear Physics Institute, Gatchina, 188300, Russia
³ Thomas Jefferson National Accelerator Facility, Newport News, VA, 23606, USA
⁴ Carnegie Mellon University, Pittsburgh, PA, 15213, USA

^* e-mail: klempt@hiskp.uni-bonn.de

Received: 2 November 2019
Accepted: 6 April 2020
Published online: 19 May 2020

Abstract

Low-energy data on the three charge states in $\gamma p \rightarrow K^+(\varSigma \pi )$ from CLAS at JLab, on $K^-p\rightarrow \pi ^0\pi ^0\varLambda$ and $\pi ^0\pi ^0\varSigma$ from the Crystal Ball at BNL, bubble chamber data on $K^-p\rightarrow \pi ^-\pi ^+\pi ^{\pm }\varSigma ^{\mp }$ , 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 $\varLambda (1405)$ , and background contributions. In a fit with one isocsalar state, the $\varLambda (1405)$ 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.