Similarity Renormalization Group for chiral two- plus three-body Hamiltonians

At present, chiral effective field theory provides the most systematic QCD-based interaction for nuclear structure calculations. We present a consistent Similarity Renormalization Group (SRG) transformation of the three-body (3N) interaction at N2LO together with the two-body (NN) interaction at N3LO. We study the properties and convergence behavior of the transformed Hamiltonian in Hartree-Fock and many-body perturbation theory calculations of ground-state energies and charge radii of closed-shell nuclei across the whole nuclear chart from 4He up to 208Pb. In particular, we analyze the contributions of the NN, the induced 3N and the genuine 3N interaction. The systematics of binding energies and radii and their dependence on the SRG flow parameter after successive inclusion of these three contributions reveal a characteristic pattern hinting of significant contributions from induced higher-order many-body interactions. To reduce the influence of these contributions we discuss alternative SRG generators.