Nuclear forces from chiral Lagrangians using the method of unitary transformation II: The two-nucleon system

We employ the chiral nucleon-nucleon potential derived in [Nucl. Phys. A 63 7 (1998) 107] to study bound and scattering states in the two-nucleon syste m. At next-to-leading order, this potential is the sum of renormalized one- pion and two-pion exchange and contact interactions. At next-to-next-to-lea ding order, we have additional chiral two-pion exchange with low-energy con stants determined from pion-nucleon scattering. Alternatively, we consider the Delta(1232) as an explicit degree of freedom in the effective field the ory. The nine parameters related to the contact interactions can be determi ned by a fit to the np S- and P-waves and the mixing parameter epsilon(1) f or laboratory energies below 100 MeV. The predicted phase shifts and mixing parameters for higher energies and higher angular momenta are mostly well described for energies below 300 MeV, The S-waves are described as precisel y as in modern phenomenological potentials. We find a good description of t he deuteron properties. (C) 2000 Elsevier Science B.V. All rights reserved.