Sum rules for Higgs bosons

Abstract
We exhibit the sum rules for Higgs-boson couplings required by unitarity. We give explicit results and applications for an SU(2)×U(1) electroweak gauge theory with arbitrary Higgs multiplets. As an example, we examine the constraints on nonminimal Higgs sectors should a single neutral Higgs boson with the standard-model coupling strength to the ZZ channel be observed in Z decays.