Dependence of the leptonic decays of H±H± on the neutrino mixing angles θ13θ13 and θ23θ23 in models with neutrinophilic charged scalars

In the Higgs Triplet Model and the neutrinophilic Two-Higgs-Doublet Model the observed neutrinos obtain mass from a vacuum expectation value which is much smaller than the vacuum expectation value of the Higgs boson in the Standard Model. Both models contain a singly charged Higgs boson (H±H±) whose Yukawa coupling is directly related to the neutrino mass (i.e. a “neutrinophilic charged Higgs”). The partial decay widths of H±H± into a charged lepton and a neutrino (H±→ℓ±νH±→ℓ±ν) depend identically on the neutrino masses and mixings in the two models. We quantify the impact of the recent measurement of sin22θ13, which plays a crucial role in determining the magnitude of the branching ratio of H±→e±νH±→e±ν for the case of a normal neutrino mass ordering if the lightest neutrino mass m0<10−3 eVm0<10−3 eV. We also discuss the sizeable dependence of H±→μ±νH±→μ±ν and H±→τ±νH±→τ±ν on sin2θ23, which would enable information to be obtained on sin2θ23 and the sign of Δm312 if these decays are measured. Such information would help neutrino oscillation experiments to determine the CP-violating phase δ.