Speaker
Description
In this talk, we will analyze the production cross sections of two
neutral Higgs bosons in models with two Higgs doublets (2HDM) with
$CP$ conservation at future $e^{+}e^{-}$ colliders (specifically
ILC and CLIC). Based on a previous work, we have studied the two main
processes where the triple Higgs couplings can play an important role:
$e^{+}e^{-}\to h_{i}h_{j}\nu\bar{\nu}$ (mainly through vector boson
fusion) and $e^{+}e^{-}\to h_{i}h_{j}Z$ (similar to Higgs-strahlung)
with $h_{i}h_{j}=hh,\ hH,\ HH\ \text{or}\ AA$. The processes are
studied at all the foreseen center-of-mass energies and luminosities
of such future colliders. The results of the cross sections are presented
in benchmark planes where large triple Higgs couplings can be realized
inside the region allowed by all the relevant theoretical and experimental
constraints. We find large deviations from the SM in the production
of two SM-like Higgs bosons and sizable production cross sections
for $h_{i}h_{j}=hH$, $HH$ and \emph{$AA$ }in large parts of the
allowed parameter space. Furthermore, we explore the distributions
of the cross section with respect to the invariant mass of the final
Higgs pair. We analyze how these distributions can be used to disentangle
the resonant or non-resonant effects from the triple Higgs couplings.
We find sizable effects from $\lambda_{hhh}$, $\lambda_{hhH}$, $\lambda_{hHH}$
and $\lambda_{hAA}$, specially at large center-of-mass energies in
the $h_{i}h_{j}\nu\bar{\nu}$ production channel.
