Ξ hyperons in the nuclear medium described by chiral NLO interactions

Properties of the baryon-baryon interactions in the strangeness S = -2 sector of chiral effective field theory at the next-to-leading order (NLO) level are explored by calculating Xi single-particle potentials in symmetric nuclear matter. The results are transformed to the Xi potential in finite nuclei by a local-density approximation with convolution by a Gaussian form factor to simulate finite-range effects. The Xi potential is repulsive in a central region, and attractive in a surface area when the Xi energy is low. The attractive pocket can lower the Xi(-) s and p atomic states. The obtained binding energies in C-12 and N-14 are found to be conformable with those found in emulsion experiments at Japan's National Laboratory for High Energy Physics (KEK). K+ spectra of (K-, K+) Xi production inclusive processes on Be-9 and C-12 are also evaluated, using a semiclassical distorted wave method. The absolute values of the cross section are properly reproduced for Be-9, but the peak locates at a lower energy position than that of the experimental data. The calculated spectrum of C-12 should be compared with the forthcoming result from the new experiments recently carried out at KEK with better resolution than before. The comparison would be valuable to improve the understanding of the Xi N interaction, the parametrization of which has still large uncertainties.