  Results of an exploratory study of the antinucleon-nucleon interaction within
chiral effective field theory are reported. The antinucleon-nucleon potential
is derived up to next-to-next-to-leading order, based on a modified Weinberg
power counting, in close analogy to pertinent studies of the nucleon-nucleon
interaction. The low-energy constants associated with the arising contact
interactions are fixed by a fit to phase shifts and inelasticities provided by
a recently published phase-shift analysis of antiproton-proton scattering data.
The overall quality of the achieved description of the antinucleon-nucleon
amplitudes is comparable to the one found in case of the nucleon-nucleon
interaction at the same order. For most S-waves and several P-waves good
agreement with the antinucleon-nucleon phase shifts and inelasticities is
obtained up to laboratory energies of around 200 MeV.
