Variational calculation of the ppK- system based on chiral SU(3) dynamics
Abstract
The ppK- system, as a prototype for possible quasibound Kbar nuclei,is investigated using a variational approach. Several versions of energy dependent effective KbarN interactions derived from chiral SU(3) dynamics are employed as input, together with a realistic NN potential (Av18). Taking into account theoretical uncertainties in the extrapolations below the KbarN threshold, we find that the antikaonic dibaryon ppK- is NOT deeply bound. With the driving s-wave KbarN interaction the resulting total binding energy is B(ppK-) = 20 3 MeV and the mesonic decay width involving KbarN -> π Y is expected to be in the range 40 - 70 MeV. Properties of this quasibound ppK- system (such as density distributions of nucleons and antikaon) are discussed. The (1405), as an I=0 quasi-bound state of Kbar and a nucleon, appears to survive in the ppK- cluster. Estimates are given for the influence of p-wave KbarN interactions and for the width from two-nucleon absorption (KbarNN -> YN) processes. With inclusionof these effects and dispersive corrections from absorption, the ppK- binding energy is expected to be in the range 20 - 40 MeV, while the total decay width can reach 100 MeV but with large theoretical uncertainties.