Multi-Higgs doublet models: physical parametrization, sum rules and unitarity bounds

Understand

If the scalar sector of the Standard Model is non-minimal, one might expect multiple generations of the hypercharge-1/2 scalar doublet analogous to the generational structure of the fermions.

• In this work, we examine the structure of a Higgs sector consisting of N Higgs doublets (where N \geq 2).
• It is particularly convenient to work in the so-called charged Higgs basis, in which the neutral Higgs vacuum expectation value resides entirely in the first Higgs doublet, and the charged components of remaining N-1 Higgs doublets are mass-eigenstate fields.
• We elucidate the interactions of the gauge bosons with the physical Higgs scalars and the Goldstone bosons and show that they are determined by an Nx2N matrix.