Enhancement of the H±W∓Z vertex in the three scalar doublet model

Enhancement of the H±W∓Z vertex in the three scalar doublet model

We compute one-loop induced trilinear vertices with physical charged Higgs bosons $H^\pm$ and ordinary gauge bosons, i.e., $H^\pm W^\mp Z$ and $H^\pm W^\mp \gamma$, in the model with two active plus one inert scalar doublet fields under a $Z_2(\text{unbroken})\times \tilde{Z}_2(\text{softly-broken})$ symmetry. The $Z_2$ and $\tilde{Z}_2$ symmetries are introduced to guarantee the stability of a dark matter candidate and to forbid the flavour changing neutral current at the tree level, respectively. The dominant form factor $F_Z$ of the $H^\pm W^\mp Z$ vertex can be enhanced by non-decoupling effects of extra scalar boson loop contributions. We find that, in such a model, $|F_Z|^2$ can be one order of magnitude larger than that predicted in two Higgs doublet models under the constraints from vacuum stability, perturbative unitarity and the electroweak precision observables. In addition, the branching fraction of the $H^\pm \to W^\pm Z$ $(H^\pm \to W^\pm \gamma)$ mode can be of order 10~(1)\% level when the mass of $H^\pm$ is below the top quark mass. Such a light $H^\pm$ is allowed by the so-called Type-I and Type-X Yukawa interactions which appear under the classification of the $\tilde{Z}$ charge assignment of the quarks and leptons. We also calculate the cross sections for the processes $H^\pm \to W^\pm Z$ and $H^\pm \to W^\pm \gamma$ onset by the top quark decay $t\to H^\pm b$ and electroweak $H^\pm$ production at the LHC.

hep-ph

Moretti, Stefano

b57cf0f0-4bc3-4e02-96e3-071255366614

Rojas, Diana

55118d87-8b05-48de-bcfc-a3d7bb7c13b4

Yagyu, Kei

ecd84785-710b-4526-8b41-55ae605e633c

24 August 2015

Moretti, Stefano

b57cf0f0-4bc3-4e02-96e3-071255366614

Rojas, Diana

55118d87-8b05-48de-bcfc-a3d7bb7c13b4

Yagyu, Kei

ecd84785-710b-4526-8b41-55ae605e633c

Moretti, Stefano, Rojas, Diana and Yagyu, Kei
(2015)
Enhancement of the H±W∓Z vertex in the three scalar doublet model.
*Journal of High Energy Physics*, 2015 (08), [116].
(doi:10.1007/JHEP08(2015)116).

## Abstract

We compute one-loop induced trilinear vertices with physical charged Higgs bosons $H^\pm$ and ordinary gauge bosons, i.e., $H^\pm W^\mp Z$ and $H^\pm W^\mp \gamma$, in the model with two active plus one inert scalar doublet fields under a $Z_2(\text{unbroken})\times \tilde{Z}_2(\text{softly-broken})$ symmetry. The $Z_2$ and $\tilde{Z}_2$ symmetries are introduced to guarantee the stability of a dark matter candidate and to forbid the flavour changing neutral current at the tree level, respectively. The dominant form factor $F_Z$ of the $H^\pm W^\mp Z$ vertex can be enhanced by non-decoupling effects of extra scalar boson loop contributions. We find that, in such a model, $|F_Z|^2$ can be one order of magnitude larger than that predicted in two Higgs doublet models under the constraints from vacuum stability, perturbative unitarity and the electroweak precision observables. In addition, the branching fraction of the $H^\pm \to W^\pm Z$ $(H^\pm \to W^\pm \gamma)$ mode can be of order 10~(1)\% level when the mass of $H^\pm$ is below the top quark mass. Such a light $H^\pm$ is allowed by the so-called Type-I and Type-X Yukawa interactions which appear under the classification of the $\tilde{Z}$ charge assignment of the quarks and leptons. We also calculate the cross sections for the processes $H^\pm \to W^\pm Z$ and $H^\pm \to W^\pm \gamma$ onset by the top quark decay $t\to H^\pm b$ and electroweak $H^\pm$ production at the LHC.

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## More information

Accepted/In Press date: 5 August 2015

Published date: 24 August 2015

Additional Information:
33 pages, 24 figures, References added

Keywords:
hep-ph

Organisations:
Theory Group

## Identifiers

Local EPrints ID: 411847

URI: http://eprints.soton.ac.uk/id/eprint/411847

ISSN: 1029-8479

PURE UUID: 0b9216cf-1669-4923-bbea-f40ddb0b40e5

## Catalogue record

Date deposited: 27 Jun 2017 16:31

Last modified: 08 Jan 2022 04:10

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## Contributors

Author:
Diana Rojas

Author:
Kei Yagyu

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