Study of chirally motivated low-energy K- optical potentials

The K- optical potential in the nuclear medium is evaluated self consistently from a free-space K-N t matrix constructed within a coupled-channel chiral approach to the low-energy (K) over barN data. The chiral-model parameters are fitted to a select subset of the low-energy data plus the K- atomic data throughout the periodic table. The resulting attractive K- optical potentials are relatively 'shallow', with central depth of the real part about 55 MeV, for a fairly reasonable reproduction of the atomic data with chi (2)/N approximate to 2.2. Relatively 'deep' attractive potentials of depth about 180 MeV, which result in other phenomenological approaches with chi (2)/N approximate to 1.5, are ruled out within chirally motivated models. Different physical data input is required to distinguish between shallow and deep K- optical potentials. The (K-stop(-), pi) reaction could provide such a test, with exclusive rates differing by over stop a factor of three for the two classes of potentials. Finally, forward (K-, p) differential cross sections for the production of relatively narrow deeply bound K- nuclear states are evaluated for deep K(-)optical potentials, yielding values considerably lower than those estimated before. (C) 2001 Elsevier Science B.V. All fights reserved.