Abstract: Although discovery of the Standard Model (SM) Higgs boson with a mass close to 125 GeV has shed light on the major question regarding the origin of the mass of elementary particles, SM can not answer a series of questions such a hierarchy problem, the origin of the matter-antimatter asymmetry and the nature of the dark matter.
Two-Higgs-double models (2HDM),aimed to answer some of these questions, are simple extension of the of the SM which proposes 5 Higgs bosons, two CP-even (h and H), one CP-odd (A), and two charged (H) bosons. In the "alignment limit" of 2HDM, the observed boson can be the SM-like and there might be scalar or pseudoscalar Higgs boson lighter than the 125 GeV Higgs boson.
Several searches have been performed to investigate the existence of such bosons in the pp collisions in the CMS experiment at LHC.