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

Abstract: 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 $$(W^{\prime\pm}, \phi^{\pm}, \eta<sup>{\pm},H<sup>{\pm})$$. Our findings demonstrate that the branching ratios of decays $t\to qV$ and $t\to qh<sup>0$, 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 $Br(t\to cZ)\sim 10<sup>{-5}$, $Br(t\to c\gamma)\sim 10<sup>{-6}$ and $Br(t \to ch⁰⁾ \sim 10<sup>{-8}$ within the appropriate parameter space.