Chiral symmetry and three-nucleon forces

After a brief review of the role three-nucleon forces play in the few-nucle on systems, the chiral-perturbation-theory approach to these forces is disc ussed. Construction of the (nominal) leading- and subleading-order Born ter ms and pion-rescattering graphs contributing to two-pion-exchange three-nuc leon forces is reviewed, and comparisons are made of the types of such forc es that are used today. It is demonstrated that the short-range c term of t he Tucson-Melbourne force is unnatural in terms of power counting and shoul d be dropped. The cl;lss of two-pion-exchange three-nucleon forces then bec omes rather uniform. [S0556-2813(99)02401-2].