The vacuum expectation value $v_s$ of a Higgs triplet field $\Delta$ carrying two units of lepton number $L$ induces neutrino masses $\propto v_s$.
The neutral component of $\Delta$ gives rise to two Higgs particles, a pseudoscalar $A$ and a scalar $S$.
The most general renormalizable Higgs potential $V$ for $\Delta $ and the Standard-Model Higgs doublet $\Phi$ does not permit the possibility that the mass of either $A$ or $S$ is small, of order $v_s$, while the other mass is heavy enough to forbid the decay $Z\to A S$ to comply with LEP 1 data.
We present a model with additional dimension-6 terms in $V$, in which this feature is absent and either $A$ or $S$ can be chosen light.
Modified majoron model for cosmological anomalies · Around
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