  Many new physics models contain new particles that interact with the Higgs
boson. These particles could be produced at the LHC via gluon-gluon fusion with
an off-shell Higgs, as well as via the Drell-Yan process if charged under a
gauge group. We consider in this paper simplified scenarios where the Standard
Model is extended by one scalar or fermionic field that interacts with the
Higgs boson and we evaluate the impact of the Higgs interaction on the
production of the exotic particles at the LHC. This analysis applies in
particular to TeV scale seesaw scenarios of neutrino mass generation.
