Strangeness Enhancement in Cu-Cu and Au-Au Collisions at √sNN=200  GeV

We report new STAR measurements of midrapidity yields for the Λ, Λ¯¯¯, K0S, Ξ−, Ξ¯¯¯+, Ω−, Ω¯¯¯+ particles in Cu+Cu collisions at √sNN=200 GeV, and midrapidity yields for the Λ, Λ¯¯¯, K0S particles in Au+Au at √sNN=200 GeV. We show that, at a given number of participating nucleons, the production of strange hadrons is higher in Cu+Cu collisions than in Au+Au collisions at the same center-of-mass energy. We find that aspects of the enhancement factors for all particles can be described by a parametrization based on the fraction of participants that undergo multiple collisions.