Speaker
Description
Some interpretations of $R_{D^{(*)}}$ anomaly in $B$ meson decay using leptoquark models can also generate top quark decays through flavor changing neutral current (FCNC). In this work we focus on two leptoquarks, i.e. scalar $S_1$ and vector $U_1$ which are both singlet under the $SU(2)_L$ gauge group in the Standard Model (SM). We investigate their implications on top FCNC decays $t\to c \ell_i \ell_j$ at tree level and $t\to c V$ at 1-loop level, with $\ell$ being the SM leptons and $V=\gamma, Z, g$ being the SM gauge bosons. We utilize the $2\sigma$ parameter fit ranges from existing literatures and find that the branching ratios $Br(t\to c \ell_i \ell_j)$ at tree level can reach $10^{-6}\sim10^{-5}$ and 1-loop process $Br(t\to c g)$ can reach $10^{-9}\sim10^{-8}$. Some quick collider search prospects are also analyzed.
