Rare top-quark decays $t \to cg(g)$ in the aligned two-Higgs-doublet model

Cai, Fang-Min; Funatsu, Shuichiro; Li, Xin-Qiang; Yang, Yadong

doi:10.48550/arxiv.2202.08091

Cited by 2 publications

(3 citation statements)

References 147 publications

(268 reference statements)

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“…( 57), we show the scatter plots for the correlations of parameters in Fig. 5, where plots (a), ( 25) and (26), it is known that BR(t → ch/cZ) do not vanish when s θχ = 0. However, because we require that all parameters have to fit the chosen ranges in Eq.…”

Section: Top-fcncsmentioning

confidence: 99%

See 1 more Smart Citation

Top-quark FCNC decays, LFVs, lepton $g-2$, and $W$ mass anomaly with inert charged Higgses

Chen¹,

Chiang²,

Su³

2023

Preprint

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The observed flavor-changing neutral-current (FCNC) processes in the standard model (SM) arise from the loop diagrams involving the weak charged currents mediated by the W -gauge boson.Nevertheless, the top-quark FCNCs and lepton-flavor violating processes resulting from the same mechanism are highly suppressed. We investigate possible new physics effects that can enhance the suppressed FCNC processes, such as t → q(h, V ) with V = γ, Z, g, h →, and → γ.To achieve the assumption that the induced-FCNCs are all from quantum loops, we consider the scotogenic mechanism, where a Z 2 symmetry is introduced and only new particles carry an odd Z 2 parity. With the extension of the SM to include an inert Higgs doublet, an inert charged Higgs singlet, a vector-like singlet quark, and two neutral leptons, it is found that, with relevant constraints taken into account, the t → c(h, Z), h → µτ , and τ → γ decays can be enhanced up to the expected sensitivities in experiments. The branching ratios of h → µ + µ − /τ + τ − from only new physics effects can reach up to O(10 −3 ). Intriguingly, the resulting muon g − 2 can fit the combined data within 2σ errors, whereas the electron g − 2 can have either sign with a magnitude of O(10 −13 − 10 −12 ). In addition, we examine the oblique parameters in the model and find that the resulting W -mass anomaly observed by CDF II can be accommodated.

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Section: Top-fcncsmentioning

confidence: 99%

“…Some interesting extensions of the SM proposed to enhance the top-FCNC decays can be found in Refs. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Top-quark FCNC decays, LFVs, lepton $g-2$, and $W$ mass anomaly with inert charged Higgses

Chen¹,

Chiang²,

Su³

2023

Preprint

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“…Thus, the top-quark flavor-changing processes can serve as good candidates for investigating new physics effects. To explore the new physics effects in the rare top-quark decays, various extensions of the SM, which can reach the HL LHC sensitivity, were proposed in [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Scotogenic top-quark FCNC decays

Chen¹,

Nomura²

2022

Preprint

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Flavor-changing neutral current (FCNC) top-quark decays are highly suppressed due to the Glashow-Iliopoulos-Maiani mechanism in the standard model (SM). If t → qh, qV with V = g, γ, Z are all induced via quantum loop levels, then we investigate the effect that can enhance the top-FCNC up to the sensitivity designed at the high-luminosity (HL) LHC. Inspired by the mechanism of the scotogenic neutrino mass, we extend the SM by including Z 2 -odd colored fermions when a Z 2 discrete is imposed. The results show that by taking BR(t → ug) 0.61 × 10 −4 recently measured by ATLAS as an input, t → qγ can be indirectly bounded to be BR(t → qγ) 3.2 × 10 −6 , which is below the expected sensitivity at the HL LHC. After taking potential constraints from various experiments into account, the obtained branching ratios for the loop-induced t → qh and t → qZ decays can be O(10 −4 ), which falls within the sensitivity at the HL LHC.

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Rare top-quark decays $t \to cg(g)$ in the aligned two-Higgs-doublet model

Cited by 2 publications

References 147 publications

Top-quark FCNC decays, LFVs, lepton $g-2$, and $W$ mass anomaly with inert charged Higgses

Top-quark FCNC decays, LFVs, lepton $g-2$, and $W$ mass anomaly with inert charged Higgses

Scotogenic top-quark FCNC decays

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