Pole position of $\Lambda (1405)$ measured in $d(K^{-},n)\pi \Sigma$ reactions

Abstract

We measured a set of ${\pi }^{\pm }{\Sigma }^{\mp }$, ${\pi }^0{\Sigma }^0$, and ${\pi }^{-}{\Sigma }^0$ invariant mass spectra below and above the $\bar{K}N$ mass threshold in $K^{-}$-induced reactions on deuteron. We deduced the $S$-wave $\bar{K}N\to \pi \Sigma$ and $\bar{K}N\to \bar{K}N$ scattering amplitudes in the isospin 0 channel in the framework of a $\bar{K}N$ and $\pi \Sigma$ coupled channel. We find that a resonance pole corresponding to $\Lambda (1405)$ is located at 1417.7${}_{-7.4}^{+6.0}$(fitting errors)${}_{-1.0}^{+1.1}$(systematic errors) + $[-26.1_{-7.9}^{+6.0}$(fitting errors)${}_{-2.0}^{+1.7}$(systematic errors)]$i$ MeV/$c^2$, closer to the $\bar{K}N$ mass threshold than the value determined by the Particle Data Group.

8 pages, 5 figures

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• The K1.8BR spectrometer system at J-PARC
• Toward establishing low-lying $\Lambda$ and $\Sigma$ hyperon resonances with the $\bar{K}+d\to \pi +Y+N$ reaction

Cited by in corpus (7)

• Two-pole nature of the $\Lambda (1405)$ from lattice QCD
• Lattice QCD study of $\pi \Sigma -\bar{K}N$ scattering and the $\Lambda (1405)$ resonance
• Structure of the $\mathbf{\Lambda }(1670)$ resonance
• Pole trajectories of the $\Lambda (1405)$ helps establish its dynamical nature
• $K^{-}d\to \pi \Lambda N$ reaction with in-flight kaons for studying the $\Lambda N$ interaction
• Investigation of the $\bar{K}$--${}^6$Li Interaction and the Search for the $\Lambda (1405)$ Resonance
• Low-lying $\Lambda$ and $\Sigma$ resonances studied with the forward $K^{\ast }$ productions off the proton induced by a high-momentum $\pi$ beam