Nuclear matter in relativistic Brueckner-Hartree-Fock theory using the leading order covariant chiral interactions with local and nonlocal regulators

The simultaneous description for nuclear matter and finite nuclei has been a long-standing challenge in nuclear ab initio theory. With the success for nuclear matter, the relativistic Brueckner-Hartree-Fock (RBHF) theory with covariant chiral interactions is a promising ab initio approach to describe both nuclear matter and finite nuclei. In the description of the finite nuclei with the current RBHF theory, the covariant chiral interactions have to be localized to make calculations feasible. In order to examine the reliability and validity, in this letter, the RBHF theory with local and nonlocal covariant chiral interactions at leading order are applied for nuclear matter. The low-energy constants in the covariant chiral interactions determined with the local regularization are close to those with the nonlocal regularization. Moreover, the RBHF theory using covariant chiral interactions with local and nonlocal regulators provide equally well description of the saturation properties of nuclear matter. The present work paves the way for the implementation of covariant chiral interactions in RBHF theory for finite nuclei.