String theory constructions using D-brane physics offer a framework whereingredients like extra abelian factors in the gauge group, more than one Higgsdoublet and a generalized Green-Schwarz mechanism appear at the same time.Motivated by works towards the direction of obtaining the Standard Model inorientifold constructions, we study in the present work a Stueckelbergextension of the two-Higgs-doublet model. The distinctive features of our modelare i) a sharp decay width for the heavy gauge boson, and ii) a charged Higgsboson having two main decay channels at tree level with equal branching ratios.
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