Rare top quark decays in the minimal R-symmetric supersymmetric standard model

TL;DR

This paper investigates rare top quark decays into lighter quarks and bosons within the minimal R-symmetric supersymmetric standard model, revealing dominant contributions from gluino and rho-chargino, with predicted branching ratios below current experimental limits.

Contribution

It provides a detailed analysis of flavor-changing neutral current top decays in the minimal R-symmetric SUSY model, highlighting the dominant supersymmetric contributions and updated branching ratio predictions.

Findings

Gluino and rho-chargino dominate decay predictions.

Predicted BR(t→qg) can reach 10^{-5}–10^{-6} after constraints.

BR(t→qγ,qZ,qh) are well below experimental bounds.

Abstract

The one-loop contributions to the flavor-changing neutral current decays of the top quark into a light quark and a gauge boson or Higgs boson, namely $t\rightarrow qV,qh$, with $q$ being $u$ or $c$, and $V$ being $\gamma$, $g$, or $Z$, are analyzed in this study within the framework of the minimal R-symmetric supersymmetric standard model. The charginos in this model have been separated into two sets, i.e., $\chi$-chargino and $\rho$-chargino. The numerical results reveal that gluino or $\rho$-chargino predominantly dictate the predictions for BR($t\rightarrow qV,qh$), while the impact of neutralino or $\chi$-chargino contributions is insignificant. By incorporating the constraints imposed by the squark mixing parameters from $\bar{B}\rightarrow X_s\gamma$ and $B^0_{d,s}\rightarrow \mu^+\mu^-$, the theoretical predictions for BR($t\rightarrow qg$) can be significantly augmented to approximately $\mathcal O(10^{-5}-10^{-6})$. On the other hand, the values of BR($t\rightarrow q\gamma,qZ,qh$) are predicted to be at least four orders of magnitude below the current experimental limits.