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

Abstract

Local measurements of the Hubble constant currently disagree with the high-precision value that is inferred from the CMB under the assumption of a $\Lambda$CDM cosmology. The significance of this tension clearly motivates studying extensions of the standard cosmological model capable of addressing this outstanding issue. Broadly speaking, models that have been successful in reducing the the tension between the CMB and local measurements (without introducing additional tension in other datasets) require an additional component of the energy density in the Universe at a time close to recombination. In this contribution, 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 $\sim 1\text{TeV}$.

arXiv comment4 pages, 1 figure. Contribution to the NuPhys2019 proceedings: https://indico.cern.ch/event/818781/ . Poster can be found at https://www.dropbox.com/s/n6jizypa0wfcfto/Escudero_Poster_Nuphys2019.pdf?dl=0

References in corpus (7)

• The Cosmic Linear Anisotropy Solving System (CLASS) II: Approximation schemes
• The Carnegie-Chicago Hubble Program. VIII. An Independent Determination of the Hubble Constant Based on the Tip of the Red Giant Branch
• The Hubble Hunter's Guide
• Signatures of Relativistic Neutrinos in CMB Anisotropy and Matter Clustering
• A CMB Search for the Neutrino Mass Mechanism and its Relation to the $H_0$ Tension
• Neutrino decoupling beyond the Standard Model: CMB constraints on the Dark Matter mass with a fast and precise $N_{\mathrm{eff}}$ evaluation
• CMB Signals of Neutrino Mass Generation

Cited by in corpus (6)

• The $H_0$ Olympics: A fair ranking of proposed models
• A Step in Understanding the Hubble Tension
• The Hubble Tension as a Hint of Leptogenesis and Neutrino Mass Generation
• Cosmology Intertwined: A Review of the Particle Physics, Astrophysics, and Cosmology Associated with the Cosmological Tensions and Anomalies
• The role of CMB spectral distortions in the Hubble tension: a proof of principle
• Superhorizon perturbations: A possible explanation of the Hubble--Lemaître Tension and the Large Scale Anisotropy of the Universe