Fermionic bound states and pseudoscalar exchange

We discuss the possibility that fermions bind due to Higgs or pseudoscalar exchange. It is reasonable to believe on qualitative grounds that this can occur for fermions with a mass larger than 800-900 GeV. An exchange of a pseudoscalar boson leads in the nonrelativisitc limit to an unacceptable potential which behaves like 1/r3 at the origin. We show that this singular behaviour is smeared out when relativistic effects are included. (author)