Search for leptoquarks and 4th generation quarks at CDF

At Run II of the Fermilab Tevatron, the CDF experiment provides good sensitivity for either discovery or setting limits on 1st and 2nd generation scalar, or 3rd generation vector, leptoquark pair-production, where each leptoquark decays to a charged lepton and a quark with variable branching ratio β, or decays to a neutrino and quark with branching ratio (1 - β). By comparison with the theoretical expectations, we set mass limits, in some cases as a function of β. New quark generations are predicted in various scenarios for physics beyond the Standard Model. Here we include results from searches for t' and for b' production. The t' is searched for in decays to Wq and the b' in decays to Z0b. All of these measurements are based on an integrated luminosity of 200-350 pb-1, taken at √s = 1.96 TeV