Z-]B(B)OVER-BAR VERSUS DYNAMICAL ELECTROWEAK SYMMETRY-BREAKING INVOLVING THE TOP-QUARK

In models of dynamical electroweak symmetry breaking which sensitively involve the third generation, such as top quark condensation, the effects of the new dynamics can show up experimentally in Z→bb̄. We compare the sensitivity of Z→bb̄ and top quark production at the Fermilab Tevatron to models of the new physics. Z→bb̄ is a relatively more sensitive probe to new strongly coupled U(1) gauge bosons, while it is generally less sensitive a probe to new physics involving color octet gauge bosons than is top quark production itself. Nonetheless, to accommodate a significant excess in Z→bb̄ requires choosing model parameters that may be ruled out within run I(b) at the Tevatron. © 1995 The American Physical Society.