### Abstract

When a small vacuum expectation value of Higgs triplet (휐∆) in the type-II seesaw model is required to explain neutrino oscillation data, a fine-tuning issue occurs on the mass-dimension lepton-number-violation (LNV) scalar coupling. Using the scotogenic approach, we investigate how a small LNV term is arisen through a radiative correction when an Z2-odd vector-like lepton (X) and an Z2-odd right-handed Majorana lepton (N) are introduced to the type-II seesaw model. Due to the dark matter (DM) direct detection constraints, the available DM candidate is the right-handed Majorana particle, whose mass depends on and is close to the m_{X} parameter. Combing the constraints from the DM measurements, the h → γγ decay, and the oblique T -parameter, it is found that the preferred range of v∆ is approximately in the region of 10^{−5}−10^{−4} GeV; the mass difference between the doubly and the singly charged Higgs is less than 50 GeV, and the influence on the h → Z γ decay is not significant. Using the constrained parameters, we analyze the decays of each Higgs triplet scalar in detail, including the possible three-body decays when the kinematic condition is allowed. It is found that with the exception of doubly charged Higgs, scalar mixing effects play an important role in the Higgs triplet two-body decays when the scalar masses are near-degenerate. In the non-degenerate mass region, the branching ratios of the Higgs triplet decays are dominated by the three-body decays.

Original language | English |
---|---|

Article number | 5 |

Journal | Journal of High Energy Physics |

Volume | 2019 |

Issue number | 10 |

DOIs | |

Publication status | Published - 2019 Oct 1 |

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### All Science Journal Classification (ASJC) codes

- Nuclear and High Energy Physics

### Cite this

*Journal of High Energy Physics*,

*2019*(10), [5]. https://doi.org/10.1007/JHEP10(2019)005

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*Journal of High Energy Physics*, vol. 2019, no. 10, 5. https://doi.org/10.1007/JHEP10(2019)005

**Radiatively scotogenic type-II seesaw and a relevant phenomenological analysis.** / Chen, Chuan Hung; Nomura, Takaaki.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Radiatively scotogenic type-II seesaw and a relevant phenomenological analysis

AU - Chen, Chuan Hung

AU - Nomura, Takaaki

PY - 2019/10/1

Y1 - 2019/10/1

N2 - When a small vacuum expectation value of Higgs triplet (휐∆) in the type-II seesaw model is required to explain neutrino oscillation data, a fine-tuning issue occurs on the mass-dimension lepton-number-violation (LNV) scalar coupling. Using the scotogenic approach, we investigate how a small LNV term is arisen through a radiative correction when an Z2-odd vector-like lepton (X) and an Z2-odd right-handed Majorana lepton (N) are introduced to the type-II seesaw model. Due to the dark matter (DM) direct detection constraints, the available DM candidate is the right-handed Majorana particle, whose mass depends on and is close to the mX parameter. Combing the constraints from the DM measurements, the h → γγ decay, and the oblique T -parameter, it is found that the preferred range of v∆ is approximately in the region of 10−5−10−4 GeV; the mass difference between the doubly and the singly charged Higgs is less than 50 GeV, and the influence on the h → Z γ decay is not significant. Using the constrained parameters, we analyze the decays of each Higgs triplet scalar in detail, including the possible three-body decays when the kinematic condition is allowed. It is found that with the exception of doubly charged Higgs, scalar mixing effects play an important role in the Higgs triplet two-body decays when the scalar masses are near-degenerate. In the non-degenerate mass region, the branching ratios of the Higgs triplet decays are dominated by the three-body decays.

AB - When a small vacuum expectation value of Higgs triplet (휐∆) in the type-II seesaw model is required to explain neutrino oscillation data, a fine-tuning issue occurs on the mass-dimension lepton-number-violation (LNV) scalar coupling. Using the scotogenic approach, we investigate how a small LNV term is arisen through a radiative correction when an Z2-odd vector-like lepton (X) and an Z2-odd right-handed Majorana lepton (N) are introduced to the type-II seesaw model. Due to the dark matter (DM) direct detection constraints, the available DM candidate is the right-handed Majorana particle, whose mass depends on and is close to the mX parameter. Combing the constraints from the DM measurements, the h → γγ decay, and the oblique T -parameter, it is found that the preferred range of v∆ is approximately in the region of 10−5−10−4 GeV; the mass difference between the doubly and the singly charged Higgs is less than 50 GeV, and the influence on the h → Z γ decay is not significant. Using the constrained parameters, we analyze the decays of each Higgs triplet scalar in detail, including the possible three-body decays when the kinematic condition is allowed. It is found that with the exception of doubly charged Higgs, scalar mixing effects play an important role in the Higgs triplet two-body decays when the scalar masses are near-degenerate. In the non-degenerate mass region, the branching ratios of the Higgs triplet decays are dominated by the three-body decays.

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U2 - 10.1007/JHEP10(2019)005

DO - 10.1007/JHEP10(2019)005

M3 - Article

AN - SCOPUS:85073602475

VL - 2019

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

SN - 1126-6708

IS - 10

M1 - 5

ER -