Two-Higgs-doublet models and the Yukawa process at LEP1

Abstract

We investigate the production of Higgs bosons $A/h$ via the Yukawa process $Z\text{ra}f\bar{f}\text{ra}f\bar{f}A/h$ taking into account QCD corrections and fermion mass effects. We estimate the discovery reach of this process and/or bounds on the parameter space of two-Higgs doublet models which can be derived from the analysis of $b\bar{b}{\tau }^{+}{\tau }^{-}$ events at LEP1. These limits have important consequences for extended models of electroweak interactions and their experimental verification/improvement are welcome.

Comments: 9 pages, Latex, 2 figures in uuencoded Postscript format, for correspondence: kalino@fuw.edu.pl, krawczyk@fuw.edu.pl