Equation of state and the nucleon optical potential with three-body forces

We report microscopic calculations of the equation of state of symmetric nuclear matter and the nucleon-nucleus optical potential in the Brueckner-Hartree-Fock approach. The calculations use several internucleon (NN) potentials, such as the Hamada-Johnston, Urbana v14, Argonne v14, Argonne v18, Reid93, and Nijm II along with and without two types of three-body forces (TBFs): the Urbana IX model and the phenomenological density-dependent three-nucleon interaction model of Lagris and Pandharipande and Friedman and Pandharipande. The inclusion of TBFs helps to reproduce the saturation properties for symmetric nuclear matter rather well as expected. The proton-nucleus optical potential has been calculated by folding the calculated reaction matrices (with and without three-body forces) over the nucleon density distributions obtained from the relativistic mean-field theory. The results show that the inclusion of TBFs reduces the strength of the central part of the optical potential in the nuclear interior and affects the calculated spin-orbit potential only marginally. As a test of the calculated potential, we have analyzed proton differential elastic scattering, analyzing power, and spin-rotation data from 40Ca and 208Pb at 65 and 200 MeV. It is observed that the inclusion of TBFs improves the agreement with the experiment especially for the polarization data.