2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/192072Upper bounds for neutral as well as charged Higgs boson masses in a two-doublet model are obtained on the basis of tree unitarity conditions à la Lee, Quigg and Thacker. A wide variety of scattering processes are considered so extensively that our bounds are more restrictive than those obtained previously for neutral Higgs bosons and are also of a new kind for charged Higgs boson. It is argued that at least one of the Higgs bosons should be lighter than 580 ${\rm GeV}/c^{2}$.15pages, 2 figures (not included but available upon request), OS-GE 32-93High Energy Physics - Phenomenologytext