Could the Hubble Tension be Pointing Toward the Neutrino Mass Mechanism?

Local measurements of the Hubble constant currently disagree with the high-precision value that is inferred from the CMB under the assumption of a ΛCDM cosmology. The significance of this tension clearly motivates studying extensions of the standard cosmological model capable of addressing this outstanding issue. In this poster, based on ArXiv:1909.04044, I will show that the Majoron - a pseudo-Goldstone boson arising from the spontaneous breaking of a global lepton number symmetry and often associated with the neutrino mass mechanism - can help to reduce the Hubble tension. Importantly, I will also show that current CMB observations can constrain neutrino-Majoron couplings as small as 10^{−13}, which within the type-I seesaw mechanism correspond to scales of lepton number breaking as high as ∼1TeV.