  We investigate the effects of chiral NNLO three-nucleon force (3NF) on
nucleus-nucleus elastic scattering, using a standard prescription based on the
Brueckner-Hartree-Fock method and the g-matrix folding model. The g-matrix
calculated in nuclear matter from the chiral N3LO two-nucleon forces (2NF) is
close to that from the Bonn-B 2NF. Because the Melbourne group have already
developed a practical g-matrix interaction by localizing the nonlocal g-matrix
calculated from the Bonn-B 2NF, we consider the effects of chiral 3NF, in this
first attempt to study the 3NF effects, by modifying the local Melbourne
g-matrix according to the difference between the g-matrices of the chiral 2NF
and 2NF+3NF. For nucleus-nucleus elastic scattering, the 3NF corrections make
the folding potential less attractive and more absorptive. The latter novel
effect is due to the enhanced tensor correlations in triplet channels. These
changes reduce the differential cross section at the middle and large angles,
improving the agreement with the experimental data for 16O-16O scattering at 70
MeV/nucleon and 12C-12C scattering at 85 MeV/nucleon.
