Top Quark Yukawa Couplings and New Physics

Abstract

We discuss associated production of a Higgs boson with a pair of $t\bar{t}$ quarks at a future high energy $e^{+}{e}^{-}$ collider. The process $e^{+}{e}^{-}\to t\bar{t}h$ is particularly sensitive to the presence of new physics and we consider the MSSM and models with extra dimensions at the $TeV$ scale as examples.

Comments: Talk given at the 5th International Collider Workshop (LCWS 2000), Fermilab, Batavia, Il, Oct 24-28, 2000