CP-odd contributions to the $ZZ^\ast\gamma$, $ZZ\gamma^\ast$, and $ZZZ^\ast$ vertices induced by nondiagonal charged scalar boson couplings

摘要

In models with extended scalar sectors with several Higgs multiplets, such asHiggs triplet models, the $Z$ gauge boson can have nondiagonal couplings tocharged Higgs bosons. In a model-independent way, we study the potentialcontributions arising from such theories to the CP-violating trilinear neutralgauge boson couplings $ZZ^*\gamma$, $ZZ\gamma^*$, and $ZZZ^*$, which areparametrized by four form factors: $h^Z_{1,2}$, $f_4^\gamma$, and $f_4^Z$,respectively. Such form factors can only be induced if there are at least twonondegenerate charged Higgs scalars and an imaginary phase in the couplingconstants. For the masses of the charged scalar bosons we consider values above300 GeV and find that the form factors can reach the following orders ofmagnitude: $|h_1^Z|\sim 10^{-5}-10^{-4}$, $|h_2^Z|\sim 10^{-7}-10^{-6}$,$|f_4^\gamma|\sim 10^{-5}-10^{-3}$ and $|f_4^Z|\sim 10^{-6}-10^{-5}$, thoughthere could be an additional suppression factor arising from the couplingconstants. We also find that the form factors decouple at high energies and arenot very sensitive to a change in the masses of the charged scalar bosons.Apart from a proportionality factor, our results for the $f_4^Z$ form factor,associated with the $ZZZ^*$ vertex, is of the same order of magnitude than thatinduced via nondiagonal neutral scalar boson couplings in the framework of atwo-Higgs doublet model.