$K^-pp$ system with chiral SU(3) effective interaction

The $K^-pp$ system is investigated using a variational approach with realistic two-body interactions: the Argonne v18 $NN$ potential and an energy dependent $\bar{K}N$ effective interaction derived from chiral SU(3) coupled-channel dynamics. Uncertainties in subthreshold extrapolations of the $\bar{K}N$ interaction are considered. A weakly bound $K^-pp$ state is found, with a binding energy $B = (19\pm 3)$ MeV substantially smaller than suggested in previous calculations. The decay width $\Gamma(K^-pp\to \pi\Sigma N)$ is estimated to range between about 40 and 70 MeV.