arXiv subjects

Yu-Ju Peng

Publications and source records attributed to Yu-Ju Peng.

3 recordsLinked to original sources

arXiv2026

Top-quark flavor-changing neutral currents and charged-lepton flavor violation in a generational three-Higgs-doublet model

In this work, we systematically investigate top-quark flavor-changing neutral-current decays, charged-lepton flavor-violating processes, and coherent $\mu-e$ conversion in the CP-conserving generational three-Higgs-doublet model (G3HDM), including the relevant tree-level and one-loop contributions. The 4839-point sample passes conservative sufficient vacuum-stability conditions, necessary perturbative-unitarity preselection cuts, Higgs-mass and signal-strength constraints, electroweak precision data, the UTfit 2025 neutral-meson-mixing ranges, $\overline{B}\to X_s\gamma$, and $B_s\to\mu^+\mu^-$. In the scanned region, $\mathrm{Br}(t\to c h_1)\leq 1.04\times10^{-5}$ and $\mathrm{Br}(h_1\to\mu\tau)\leq 4.83\times10^{-4}$, while the maximal conversion rates are $\mathrm{CR}(\mu\mathrm{Al}\to e\mathrm{Al})\approx 4.95\times10^{-15}$ and $\mathrm{CR}(\mu\mathrm{Au}\to e\mathrm{Au})\approx 1.05\times10^{-14}$. The dominant collider signals are mainly driven by tree-level flavor-changing neutral-Higgs couplings, which determine the relative strengths of these processes and induce the pronounced enhancement of $t\to c h_1$ and $h_1\to\mu\tau$. Meanwhile, the upper range of the predicted $\mu-e$ conversion rate in aluminum lies within the sensitivity reach of next-generation $\mu-e$ conversion experiments.

hep-ph↗

arXiv2026

Lepton-flavor violation and muon $(g-2)$ in the flavor-dependent $U(1)_F$ model

Lepton flavor violation (LFV) processes are forbidden in the standard model (SM), hence the observation of LFV transitions would represent a clear signal of new physics beyond the SM. In this work, we investigate the muon anomalous magnetic dipole moments (MDM) and LFV processes $l_{j}^{-}\to l_{i}^{-}\gamma $ and $l_{j}^{-}\to l_{i}^{-}l_{i}^{-}l_{i}^{+}$ in the extension of the SM with $U(1)_F$ local gauge symmetry (FDM). The muon anomalous MDM is one of the most precisely measured quantities in particle physics, which can be used to constrain the contributions from new couplings in the FDM. The newly incorporated $U(1)_F$ charges are correlated with the flavor properties of fermions, hence the newly added Yukawa couplings make contributions to these LFV processes. Considering the latest experimental constraints on the muon anomalous MDM, the new interactions in the FDM can make significant contributions to the LFV processes $l_{j}^{-}\to l_{i}^{-}\gamma $ and $l_{j}^{-}\to l_{i}^{-}l_{i}^{-}l_{i}^{+}$, the predicted branching ratios can well reach the future experimental sensitivity.

hep-ph↗

arXiv2026

Flavor-Violating Higgs and Top Decays in the Type 1B Flavorful Two-Higgs-Doublet Model with a Twist

We study flavor-violating decays of the SM-like Higgs boson and rare top decays in the Type 1B realization of the flavorful two-Higgs-doublet model with a twist, focusing on $h\to sb$, $h\to db$, $h\to uc$, $h\to\mu\tau$, $h\to e\tau$, $h\to e\mu$, $t\to ch$, and $t\to uh$. We present the relevant amplitude and branching-ratio formulae, include one-loop vertex corrections, and impose constraints from Higgs signal-strength measurements, electroweak precision tests, meson mixing, $B\to X_s\gamma$, direct HFV searches and CLFV constraints, including $\mu-e$ conversion. The surviving parameter space favors $\mathrm{BR}(h\to sb)\gg\mathrm{BR}(h\to db)$, $\mathrm{BR}(t\to ch)\gg\mathrm{BR}(t\to uh)$, and $\mathrm{BR}(h\to\mu\tau)\gg\mathrm{BR}(h\to e\tau)\sim\mathrm{BR}(h\to e\mu)$ in the lepton sector. One-loop effects usually preserve these hierarchies, but can modify individual channels through different mechanisms: sizable destructive tree--loop interference can reduce $h\to sb$ enough to yield rare $\mathrm{BR}_{\mathrm{1L}}(h\to db)>\mathrm{BR}_{\mathrm{1L}}(h\to sb)$ points, whereas the large relative corrections found in rare top decays mainly reflect strong SM-like alignment suppressing the tree-level amplitudes.

hep-ph↗