Hard $m_t$ Corrections as a Probe of the Symmetry Breaking Sector

Abstract

Non-decoupling effects related to a large $m_t$ affecting non-oblique radiative corrections in vertices ($Z\bar{b}b$) and boxes ($B$-$\bar{B}$ mixing and ${ϵ}_K$) are very sensitive to the particular mechanism of spontaneous symmetry breaking. We analyze these corrections in the framework of a chiral electroweak standard model and find that there is only one operator in the effective lagrangian which modifies the longitudinal part of the $W^{+}$ boson without touching the oblique corrections. The inclusion of this operator affects the $Z\bar{b}b$ vertex, the $B$-$\bar{B}$ mixing and the CP-violating parameter ${ϵ}_K$, generating interesting correlations among the hard $m_t^4\log m_t^2$ corrections to these observables, for example, the maximum vertex $Zb\bar{b}$ correction allowed by low energy physics is about one percent.

Comments: LaTex, 8 pages, 1 postscript figure included