Flavor-changing top quark rare decays in the Bestest Little Higgs Model

This paper investigates the effects of parameters in the Bestest Little Higgs Model (BLHM) on rare flavor-changing decays of the top quark. As a result, flavor-changing phenomena are introduced in the BLHM for the first time. In this study, we incorporate new flavor mixing terms between the light quarks of the Standard Model (SM) and the fermions and bosons of the BLHM. We compute the one-loop contributions from the heavy quark $(B)$ and the heavy bosons $(W^{\prime\pm}, \phi^{\pm}, \eta^{\pm},H^{\pm})$. Our findings demonstrate that the branching ratios of decays $t\to qV$ and $t\to qh^0$, where $q=u,c$ and $V=Z, \gamma, g$, exhibit improvements compared to their counterparts in the SM, except for the gluon case. Moreover, we observe that the processes with higher sensitivity are $Br(t\to cZ)\sim 10^{-5}$, $Br(t\to c\gamma)\sim 10^{-6}$ and $Br(t \to ch^0) \sim 10^{-8}$ within the appropriate parameter space.Comment: 13 pages and 10 figure

Sensitivity limits on the weak dipole moments of the top-quark at the Bestest Little Higgs Model

We presented new researches for the sensitivity limits on the weak dipole moments of the top quark-$Z$ boson interactions in the context of the Bestest Little Higgs Model (BLHM). For this purpose, we derive the corresponding Feynman rules. Among the new contributions, there are those arising from the vertices of scalar bosons, vector bosons and heavy quarks contribution: $tq_iS_i$, ($S_i=h_0, H_0, A_0, \phi^{0}, \eta^{0}, \sigma, H^{\pm}, \phi^{\pm}, \eta^{\pm}$); $tq_iV_i$, ($V_i= \gamma, Z, W, Z', W'$); and $Zq_i\bar q_i$ ($q_i=b, t, B, T, T_5, T_6, T^{2/3}, T^{5/3}$). With these new vertices, we calculate the one-loop contributions to the weak dipole moments $a^W_t$ and $d^W_t$ of the top-quark in several scenarios. We found that with the parameters of the BLHM of $m_{A_0}= 1000$ GeV, $m_{\eta^0}= 100$ GeV, $F=4000$ GeV, $f=[1000, 3000]$ GeV and $\tan\beta=3$, the $a^W_t$ reaches values with a sensitivity of $a^{W}_{t}= 2.49 \times 10^{-4}-1.26 \times 10^{-5}i$, $1.26 \times 10^{-4}-5.41\times 10^{-6}i$, where the main contribution comes from the scalars $h_0$ and $H_0$, which couples to the top-quark of the Standard Model and the top-quarks of the BLHM. These values seem to be out of the reach of the expected experimental sensitivity of present experiments. However, experiments on future colliders are expected to be sensitive enough to measure the AWMDM of the top-quark. Our study complements other studies at the level of one-loop with an extended scalar sector.Comment: 48 pages, 21 figure

Research on the electromagnetic and weak dipole moments of the tau-lepton at the Bestest Little Higgs Model

In this paper, using the Bestest Little Higgs Model (BLHM) we calculate at the one-loop level the contributions to the Anomalous Magnetic Dipole Moment (AMDM) and Anomalous Weak Magnetic Dipole Moment (AWMDM) of the tau-lepton. The implications from this model are studied, emphasizing the contributions of the new physics induced by the new scalar and vector bosons of the BLHM: $$S_i=H_0, A_0, \phi ^{0}, \eta ^{0}, \sigma , H^{\pm }, \phi ^{\pm }, \eta ^{\pm }$$, and $$V_i=Z', W'^{\pm }$$ because these quantify the new physics. With these new contributions, we estimated bounds on the real and imaginary parts of the AMDM and AWMDM of the tau-lepton. Our study complements other one-loop-level research performed on models beyond the Standard Model

Flavor-changing top quark rare decays in the Bestest Little Higgs Model

Abstract This paper investigates rare flavor-changing decays of the top quark in the Bestest Little Higgs Model (BLHM). As a result, flavor-changing phenomena are introduced in the BLHM for the first time. In this study, we incorporate new flavor mixing terms between the light quarks of the Standard Model (SM) and the fermions and bosons of the BLHM. We compute the one-loop contributions from the heavy quark (B) and the heavy bosons $$(W^{\prime \pm }, \phi ^{\pm }, \eta ^{\pm },H^{\pm })$$ ( W ′ ± , ϕ ± , η ± , H ± ) . Our findings demonstrate that the branching ratios of decays $$t\rightarrow qV$$ t → q V and $$t\rightarrow qh^0$$ t → q h 0 , where $$q=u,c$$ q = u , c and $$V=Z, \gamma , g$$ V = Z , γ , g , can reach larger branching ratios compared to their counterparts in the SM, except for the gluon case. Moreover, we observe that the processes with the highest sensitivity are $$Br(t\rightarrow cZ)\sim 10^{-5}$$ B r ( t → c Z ) ∼ 10 - 5 , $$Br(t\rightarrow c\gamma )\sim 10^{-6}$$ B r ( t → c γ ) ∼ 10 - 6 and $$Br(t \rightarrow ch^0) \sim 10^{-8}$$ B r ( t → c h 0 ) ∼ 10 - 8 within the appropriate parameter space