Testing models with a nonminimal Higgs sector through the decay t⃗q+WZ

We study the contribution of the charged Higgs boson to the rare decay of the top quark t⃗q+WZ (q=d,s,b) in models with Higgs sectors that include doublets and triplets. Higgs doublets are needed to couple a charged Higgs boson with quarks, whereas the Higgs triplets are required to generate the nonstandard vertex HWZ at the tree level. It is found that within a model that respects the custodial SU(2)_c symmetry and avoids flavor-changing neutral current (FCNC) by imposing discrete symmetries, the decay mode t⃗b+WZ can reach a branching ratio (BR) of order 10^-2, whereas the decay modes t⃗(d,s)+WZ, can reach a similar BR in models where FCNC are suppressed by flavor symmetries.