125 GeV Higgs boson rare decays in a flavor-dependent $U(1)_F$ model

Abstract

In this work, we analyze the Higgs boson decay channels, specifically, $h{\rightarrow}γγ$, $h{\rightarrow} VV^*$ (with $V=Z,W$), and $h{\rightarrow} f\bar{f}$ (for $f=b,c,τ$) within the flavor-dependent $U(1)_F$ model (FDM). We also investigate processes induced by flavor-changing neutral currents, including the decays $\bar B \to X_sγ$ and $B_s^0 \to μ^+μ^-$, the top quark decays $t\to c h$ and $t\to u h$, and the lepton flavor-violating decays $τ\to 3e$, $τ\to 3μ$, and $μ\to 3e$. Furthermore, we incorporate the electroweak precision observables constraints via the S, T, and U parameters. Compared to the Standard Model, the scalar sector of the FDM is extended by two Higgs doublets and one Higgs singlet, which affects the 125 GeV Higgs properties significantly. Meanwhile, the decays $h{\rightarrow} Zγ$, $h\rightarrow MZ$, and $h{\rightarrow} Mγ$ (where $M$ is a vector meson $(ρ,ω,φ,J/Ψ,Υ)$ of the Standard-Model-like Higgs are studied, and we illustrate how changes in the scalar sector and the Yukawa coupling influence the signal strengths for the 125 GeV Higgs decay channels and the Higgs mass in the FDM.

Figures (9)

• Figure 1: The dominating Feynman diagrams for $h{\rightarrow} MZ$, where $M$ is a vector meson ($\rho, \omega, \phi, J/\psi, \Upsilon$) HVZ-sm.
• Figure 2: The one-loop diagrams for $h{\rightarrow} \gamma Z$ in the FDM, with $F$ denoting charged fermions and $S=H^{\pm}$ denoting charged Higgs, $W$ is $W^\pm$ boson.
• Figure 3: Direct (left and center) and indirect (right) contributions to the $h\to M\gamma$ decay amplitude. The crossed circle in the third diagram denotes the off-shell $h\to\gamma\gamma^*$ and $h\to\gamma Z^*$ amplitudes, which in the SM arise first at one-loop order.
• Figure 4: The plots show $m_{h}$ versus $\lambda_2$ (a), $m_{h}$ versus $\lambda_9$ (b), $m_{h}$ versus $\lambda_2$ (c), and $m_{h}$ versus $v_1$ (d), where the solid, dashed and dotted curves represent the results for $\lambda_\chi=2,\;3,\;4$ respectively. The light green areas indicate the range of $124\;{\rm GeV}<m_{h}<126\;{\rm GeV}$.
• Figure 5: Scanning the parameter space in Table \ref{['tab-scan']} keeping $\;\lambda_1=\lambda_2=\lambda_4=\lambda_5=\lambda_6=\lambda_7=\lambda_8=2,\;$and $\kappa=-1\;{\rm TeV}$, and the results of $v_1-\left |Z_{h,11} \right |$ (a), $v_1-\left |Z_{h,12} \right |$ (b), and $v_1-\left |Z_{h,13} \right |$ (c) are plotted, where the green triangle denotes the best fit point $\chi ^2=3.94$.