Abstract
Z.Phys. C74 (1997) 93-111 The production mechanisms and decay modes of the heavy neutral and charged
Higgs bosons in the Minimal Supersymmetric Standard Model are investigated at
future $e^+ e^-$ colliders in the TeV energy regime. We generate supersymmetric
particle spectra by requiring the MSSM Higgs potential to produce correct
radiative electroweak symmetry breaking, and we assume a common scalar mass
$m_0$, gaugino mass $m_{1/2}$ and trilinear coupling $A$, as well as gauge and
Yukawa coupling unification at the Grand Unification scale. Particular emphasis
is put on the low $\tb$ solution in this scenario where decays of the Higgs
bosons to Standard Model particles compete with decays to supersymmetric
charginos/neutralinos as well as sfermions. In the high $\tb$ case, the
supersymmetric spectrum is either too heavy or the supersymmetric decay modes
are suppressed, since the Higgs bosons decay almost exclusively into $b$ and
$\tau$ pairs. The main production mechanisms for the heavy Higgs particles are
the associated $AH$ production and $H^+H^-$ pair production with cross sections
of the order of a few fb.