Tests of Improved Kogut-Susskind Fermion Actions
  Improved Kogut-Susskind quark actions containing repeatedly smeared links are studied to address the issue of flavor symmetry restoration. As a measure of the flavor symmetry restoration the mass spectrum of all the pions is computed. We present results for several variants of the "fat" actions that are suitable for full QCD simulations. 
Kostas Orginos and Doug Toussaint