Nuclear forces from EFT: Recent developments

¹ Helmholtz-Institut für Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn, Germany
² Forschungszentrum Jülich, Institut für Kernphysik (IKP-3) and Jülich Center for Hadron Physics, D-52425 Jülich, Germany
³ Forschungszentrum Jülich, Institut für Kernphysik (IKP-3), Institite for Advanced Simulation (IAS-4) and Jülich Center for Hadron Physics, D-52425 Jülich, Germany

^a e-mail: hkrebs@itkp.uni-bonn.de

Abstract

Nuclear forces are considered based on chiral perturbation theory with and without explicit ∆-isobar degrees of freedom. We discuss the subleading corrections to chiral three-nucleon forces in the ∆-less formalism which contain no additional free parameters. In the formalism with explicit ∆-isobar we present the complete next-to-next-to-leading order analysis of isospin-conserving and next-to-leading order analysis of isospinviolating nuclear forces. The perturbative expansion of nuclear forces in the ∆-full case is shown to have much better convergence compared with the ∆-less theory where the ∆-resonance is integrated out and is encoded in certain low-energy constants.