Dynamical coupled-channels model of K- p reactions. II. Extraction of Λ* and Σ* hyperon resonances

Resonance parameters (pole masses and residues) associated with the excited states of hyperons, Lambda* and Sigma*, are extracted within a dynamical coupled-channels model developed recently by us [Phys. Rev. C 90, 065204 (2014)] through a comprehensive partial-wave analysis of the K- p --> (K) over bar N, pi Sigma, pi Lambda, eta Lambda, K Xi data up to invariant mass W = 2.1 GeV. We confirm the existence of resonances corresponding to most, if not all, of the four-star resonances rated by the Particle Data Group. We also find several new resonances, and in particular propose a possible existence of a new narrow J(P) = 3/2(+) Lambda resonance that couples strongly to the eta Lambda channel. The J(P) = 1/2(-) Lambda resonances located below the (K) over bar N threshold are also discussed. Comparing our extracted pole masses with the ones from a recent analysis by the Kent State University group, some significant differences in the extracted resonance parameters are found, suggesting the need of more extensive and accurate data of K- p reactions including polarization observables to eliminate such an analysis dependence of the resonance parameters. In addition, the determined large branching ratios of the decays of high-mass resonances to the pi Sigma* and (K) over bar *N channels also suggest the importance of the data of 2 --> 3 reactions such as K- p --> pi pi Lambda and K- p --> pi(K) over bar N. Experiments on measuring cross sections and polarization observables of these fundamental reactions are highly desirable at hadron beam facilities such as J-PARC for establishing the Lambda* and Sigma* spectrum.