ρ parameter and H0 → lilj in models with TeV sterile neutrinos

The presence of massive sterile neutrinos N mixed with the active ones induces flavor violating processes in the charged lepton sector at the loop level. In particular, the amplitude of H-0 -> (l) over bar (i)l(j) is expected to be proportional to the product of heavy-light Yukawa couplings y(i)y(j) = 2s(vi)s(vj) m(N)(2)/v(2), where s(vi,j) express the heavy-light neutrino mixings. Here, we revisit these Higgs decays in the most generic extension of the neutrino sector, focusing on large values of y(i). We show that decoupling effects and a cancellation between the two dominant contributions to these processes makes the amplitude about 100 times smaller than anticipated. We fmd that perturbative values of y(i) giving an acceptable contribution to the rho parameter imply B(H-0 -> (l) over bar (i)l(j)) < 10(-8) for any lepton flavors, a rate that is not accessible at current colliders.