The Two-Higgs-Doublet-Model (2HDM) of Type-II is a simple extension of the SM, only introducing two
Higgs doublets with hypercharge Y=1
as additional fields leading to five physical Higgs boson states. Three of these physical
are electrically neutral and two states H±
The free parameters of the 2HDM are the Higgs boson masses
tanβ, the ratio of the vaccuum expectation values of the two Higgs
doublets and the Higgs mixing angle α.
In the 2HDM of Type-II one Higgs doublet only couples to up-type
quarks while the other only couples to down-type quarks.
In the analysis only observables are considered that are sensitive to corrections
from the exchange of charged Higgs bosons and we derive limits on the allowed
charged Higgs mass MH±
and tanβ only.
Results on constraints of the 2HDM can be found in the Gfitter publication Revisiting the Global Electroweak Fit of the Standard Model and Beyond with Gfitter