Top-Bottom Color and Weak Doublets Seesaw∗

A brief overview of some of the last decade’s developments in the Topmode/Topcolor class of models is presented. In addition, a new Topcolor type scenario, named Top-Bottom Color, is suggested. A seesaw mechanism with new weak doublet quarks has been introduced to lower the previous theoretical prediction for the large top quark mass; without a seesaw mechanism and with a low scale of Nambu Jona-Lasinio triggering interactions, the top quark mass was predicted to be O(500GeV). In Top-Bottom Color an effective, composite two Higgs doublet model is obtained where the third generation isospin splitting is introduced via tilting interactions related to the broken non-abelian gauge groups (i.e. without strong, triviality-sensitive U(1) groups). To complete discussion a few notes on the fine tuning related to the bottom quark mass are appended in an addenum. A generic problem (Why does the top Yukawa coupling equal one?) of the Top-mode/Topcolor class of models is pointed out as well. Furthermore, previous work on the third generation seesaw mechanism with weak doublet quarks and dynamical top mass production in the Topcolor spirit is discussed. Talk given at the Thinkshop-top quark physics for RUN II and beyond, Fermilab, November 10-12, 2000. e-mail address: [email protected]