Three-Nucleon Forces for the New Millennium

Abstract

Most nuclear physics ranges from insensitive to relatively insensitive to many-nucleon forces. The dominant ingredient in calculations of nuclear properties is the nucleon-nucleon potential. Three-nucleon forces nevertheless play an important role in nuclear physics because of the great precision of modern calculational methods for systems of relatively few nucleons. We explore the reasons why many-body forces are weak in nuclei by using a classification scheme for such forces that is based on dimensional power counting, which is used to organize chiral perturbation theory. An assessment will be made of how close we are to a ``standard'' three-nucleon force. Recent advances in determining the significance of three-nucleon forces will also be discussed.Comment: Invited talk presented at XVIth International Conference on Few-Body Problems in Physics, Taipei, Taiwan, March 6-10, 2000. -- 9 pages, latex, 3 figures -- To appear in Nuclear Physics A -- fleqn.sty, espcrc1.sty, and epsfig.sty require