Anatomy of top-mode extended technicolor model

We analyze two versions of the extended technicolor (ETC) incorporating the top quark condensate via the flavor-universal coloron type topcolor SU(3)1xSU(3)2: A straightforward top-mode ETC having quarks and techniquarks assigned to a single (strong) SU(3)1, and a 'twisted model' with techniquarks carrying the weak SU(3)2 while quarks the strong SU(3)1. The straightforward model has the same ETC structure as that of Appelquist et al. without topcolor which we first analyze to find that it yields only too small ETC-induced mass for the third generation. In contrast, our model having topcolor takes the form of a version of the topcolor-assisted technicolor (TC2) after ETC breakings, which triggers the top quark condensate giving rise to a realistic top mass. However, techniquarks have the strong topcolor SU(3)1 in addition to the already strong walking/conformal technicolor, which triggers the techniquark condensate at scale much higher than the weak scale, a disaster. We then consider a twisted model' of TC2, though not an explicit ETC. We find a new feature that 'ETC'-induced quark mass is enhanced to the realistic value by the large anomalous dimension γm≅2 of Nambu-Jona-Lasinio-type topcolor interactions. The result roughly reproduces the realistic quark masses. We further find a novel effect of the above large anomalous dimension γm≅2: The top-pion mass has a universal upper bound, mπt < 70 GeV, in the generic TC2 model. (author)