Modified majoron model for cosmological anomalies

TL;DR

This paper introduces a modified majoron model with additional dimension-6 terms allowing light scalar or pseudoscalar Higgs particles, aiming to address cosmological anomalies and neutrino observations, with testable predictions at colliders.

Contribution

The paper proposes a modified Higgs potential model that permits light scalar or pseudoscalar particles, providing a potential solution to cosmological anomalies and neutrino flux deficits.

Findings

Light Higgs particles could explain cosmological anomalies.

Model predicts charged Higgs bosons below 400 GeV.

Potential collider signatures at the LHC.

Abstract

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. Subsequently we propose the model as a remedy to cosmological anomalies, namely the tension between observed and predicted tensor-to-scalar mode ratios in the cosmic microwave background and the different values of the Hubble constant measured at different cosmological scales. Furthermore, if $\Delta$ dominantly couples to the third-generation doublet $L_\tau=(\nu_\tau,\tau)$, the deficit of $\nu_\tau$ events at IceCube can be explained. The singly and doubly charged triplet Higgs bosons are lighter than 280 GeV and 400 GeV respectively, and could be found at the LHC.