Nuclear and neutron matterG-matrix calculations with a chiral effective field theory potential including effects of three-nucleon interactions

Abstract

The energies of symmetric nuclear matter and neutron matter are evaluated in the lowest-order Brueckner theory using a chiral effective field theory potential including effects of a three-nucleon force (3NF). The 3NF is first reduced to a density-dependent nucleon-nucleon ($NN$) force by folding with single-nucleon degrees of freedom in infinite matter. Adding the reduced $NN$ force to the initial $NN$ force and applying a partial-wave expansion, $G$-matrix calculations are performed in pure neutron matter as well as in symmetric nuclear matter. A saturation curve which is close to the empirical one is obtained. It is explicitly shown that the cutoff-energy dependence of the calculated energies is substantially reduced by including the 3NF. Characteristics of 3NF contributions in separate spin and isospin channels are discussed. Calculated energies of neutron matter are very similar to those employed in the literature for considering neutron star properties.