Observational constraints on the massive neutrinos induced late-time cosmic acceleration

We study a scenario based upon a mass-less $λϕ^4$ theory coupled to massive neutrino matter with $Z_2$ symmetry using a conformal coupling, $A(ϕ)=1-αϕ^2/2M_{pl}^2;~α=M^2_{pl}/M^2$ where $M$ is a cut off mass. The chosen coupling generically leads to the spontaneous symmetry breaking at late times such that the field acquires non-zero mass, $m_ϕ=(αΩ_{0ν})^{1/2}H_0 \ll H_0$ and rolls slowly around the true ground state which emerges after spontaneous symmetry breaking. For the statistical analysis, we utilize Pantheon+Multi-Cycle Treasury and OHD data sets. We find that even a small fraction of the neutrino matter density together with its coupling to the scalar field can actually make our model to behave like a weakly dynamical dark energy and have $Λ$CDM model as a limiting case.

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