Interference bands in decays of doubly-charged Higgs bosons to dileptons in the minimal type-II seesaw model at the TeV scale

The dileptonic decays of doubly-charged Higgs bosons W:l are investigated in the minimal type-II seesaw model with one Higgs triplet A and one heavy Majorana neutrino N-1 at the TeV scale. We show that the branching ratios B(H-+/-+/- -> l alpha L-+/-beta(+/-)) depend not only on the mass and mixing parameters of three light neutrinos vi (for i = 1. 2. 3), but also on those of N-1. Assuming the mass of N-1 to lie in the range 200 GeV-1 TeV, we figure out the generous interference bands for the contributions of v(i) and N-1 to B(H-+/-+/- -> l alpha(+/-) l beta(+/-)): root|sin theta(14) sin theta(j4)| similar to 10(-8)-10(-5), where theta(i4) and theta(j4) measure the strength of charged-current interactions of NI. We illustrate some salient features of the interference bands by considering three typical mass patterns of v(i), and stress that it is very difficult to distinguish the type-II seesaw model from the triplet seesaw model in such a parameter region at the Large Hadron Collider. (c) 2008 Elsevier B.V. All rights reserved.