Tree-level unitarity constraints for the SM-like 2HDM
  We consider a Z_2-symmetric Two Higgs Doublet Model (2HDM), where the vacuum expectation values of both doublets are non-vanishing. Unitarity constraints for the SM-like 2HDM are analyzed for the mass of the lightest Higgs boson in the range [115,127] GeV. New stringent bounds on tan\beta, 0.17<tan\beta<6.10, are derived. A discussion of the source of these constraints is provided. 
Bogumila Gorczyca and Maria Krawczyk
hep-ph