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

Abstract

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.