The effects of triplet Higgs bosons in long baseline neutrino experiments

Abstract

The triplet scalars $(Δ=Δ^{++},Δ^{+},Δ^{0})$, utilized in the so-called Type-II seesaw model to explain the lightness of neutrinos, would generate nonstandard interactions (NSI) for neutrino propagating in matter. We investigate the prospects to probe these interactions in long baseline neutrino oscillation experiments. We analyze the upper bounds that the proposed DUNE experiment might set on the nonstandard parameters and numerically derive upper bounds, as function of the lightest neutrino mass, on the ratio the mass $M_Δ$ of the triplet scalars and strength $|λ_ϕ|$ of the coupling $ϕϕΔ$ of the triplet $Δ$ and conventional Higgs doublet $ϕ$ . We also discuss the possible misinterpretation of these effects as effects arising from a nonunitarity of the neutrino mixing matrix and compare the results with the bounds that arise from the charged lepton flavor violating processes.