Higgs mediated flavor-violating transitions of the top quark

Abstract

Flavor violating tuiH vertex induces top quark couplings tcy and tuiγγ (ui = u, c) at the one-loop level, in the effective Yukawa sector through dimension six SUL(2) × UY(1)-invariant operators. The t → cH and t → cγγ decays can reach branching ratios about 5 × 10−3 and 10−4 respectively. As for tc production, it is found that, due to the presence of a resonant effect in the convoluted cross section σ(e+e− → γγ → tc̄ + t̄c), about (0.5 − 2.7) × 103 tc events may be produced at the ILC for mH ∼ mt.