  We develop a dynamical coupled-channels model of K^- p reactions, aiming at
extracting the parameters associated with hyperon resonances and providing the
elementary antikaon-nucleon scattering amplitudes that can be used for
investigating various phenomena in the strangeness sector such as the
production of hypernuclei from kaon-nucleus reactions. The model consists of
(a) meson-baryon (MB) potentials v_{M'B',MB} derived from the phenomenological
SU(3) Lagrangian, and (b) vertex interactions Gamma_{MB,Y*} for describing the
decays of the bare excited hyperon states (Y*) into MB states. The model is
defined in a channel space spanned by the two-body barK N, pi Sigma, pi Lambda,
eta Lambda, and K Xi states and also the three-body pi pi Lambda and pi barK N
states that have the resonant pi Sigma* and barK* N components, respectively.
The resulting coupled-channels scattering equations satisfy the multichannel
unitarity conditions and account for the dynamical effects arising from the
off-shell rescattering processes. The model parameters are determined by
fitting the available data of the unpolarized and polarized observables of the
K^- p --> barK N, pi Sigma, pi Lambda, eta Lambda, K Xi reactions in the energy
region from the threshold to invariant mass W=2.1 GeV. Two models with equally
good chi^2 fits to the data have been constructed. The partial-wave amplitudes
obtained from the constructed models are compared with the results from a
recent partial-wave analysis by the Kent State University group. We discuss the
differences between these three analysis results. Our results at energies near
the threshold suggest that the higher partial waves should be treated on the
same footing as the S wave if one wants to understand the nature of
Lambda(1405)1/2^- using the data below the barK N threshold, as will be
provided by the J-PARC E31 experiment.
