Three Extra Mirror or Sequential Families: a Case for Heavy Higgs and Inert Doublet

Understand

We study the possibility of the existence of extra fermion families and an extra Higgs doublet.

• We find that requiring the extra Higgs doublet to be inert leaves space for three extra families, allowing for mirror fermion families and a dark matter candidate at the same time.
• The emerging scenario is very predictive: it consists of a Standard Model Higgs boson, with mass above 400\,\GeV, heavy new quarks between 340 and 500\,\GeV, light extra neutral leptons, and an inert scalar with a mass below $M_Z$.