Gravitational origin of dark matter and Majorana neutrino mass with non-minimal quartic inflation

TL;DR

This paper presents a unified gravitational framework for explaining quartic inflation, dark matter production, and Majorana neutrino masses, highlighting new results in dark matter phenomenology under non-minimal inflation.

Contribution

It introduces a minimal model linking inflation, dark matter, and neutrino masses via gravitational effects and explores the impact of non-minimal coupling and inflationary parameters.

Findings

Dark matter mass range predicted as 1 keV to 100 MeV.

DM relic density depends on non-minimal coupling and inflaton VEV.

Different inflation models yield varying DM mass ranges, up to hundreds of TeV.

Abstract

We propose a minimal framework to address successful quartic inflation, dark matter (DM) production in the early universe and non-vanishing tiny Majorana neutrino mass from a common gravitational origin point of view. In this setup, the quartic inflation is revived successfully via non-minimal coupling of inflaton to gravity while the production of DM takes place from purely gravitational effects through a misalignment mechanism. The generation of light Majorana neutrino mass is aided by explicit breaking of global lepton number symmetry through Planck suppressed operators involving non-zero vacuum expectation value (VEV) of the inflaton field. We present a detailed study of the DM yield in presence of non-minimal inflation, considering both the metric and the Palatini formalisms of gravity wherever appropriate. We reach at some interesting and different results in the DM sector compared to the earlier works in the similar direction with minimal inflationary background. Restricting to the light DM regime ($\mathcal{O}(1)$ keV- $\mathcal{O}(100)$ MeV) where classical production is expected to dominate over the quantum production, we numerically predict the DM mass by varying the DM quartic and non-minimal coupling, to be consistent with relic density requirements. We also obtain some non-trivial dependence of DM phenomenology on some of the relevant parameters of the inflation sector {\it e.g.} non minimal coupling and inflaton VEV. To explore the dependence on inflationary parameters further, we also estimate the DM relic using the same mechanism for two other inflationary models consistent with latest data and observe that one of these models predicts different range of DM mass upto hundreds of TeV.