Dark Matter from the inflaton field

Abstract

We present a model where inflation and Dark Matter takes place via a single scalar field φ. Without introducing any new parameters we are able unify inflation and Dark Matter using a scalar field φ that accounts for inflation at an early epoch while it gives a Dark Matter WIMP particle at low energies. After inflation our universe must be reheated and we must have a long period of radiation dominated before the epoch of Dark Matter. Typically the inflaton decays while it oscillates around the minimum of its potential. If the inflaton decay is not complete or sufficient then the remaining energy density of the inflaton after reheating must be fine tuned to give the correct amount of Dark Matter. An essential feature here, is that Dark Matter-Inflaton particle is produced at low energies without fine tuning or new parameters. This process uses the same coupling g as for the inflaton decay. Once the field φ becomes non-relativistic it will decouple as any WIMP particle, since n φ is exponentially suppressed. The correct amount of Dark Matter determines the cross section and we have a constraint between the coupling g and the mass mo of φ. The unification scheme we present here has four free parameters, two for the scalar potential V (φ) given by the inflation parameter λ of the quartic term and the mass mo. The other two parameters are the coupling g between the inflaton φ and a scalar filed ϕ and the coupling h between ϕ with standard model particles ψ or χ. These four parameters are already present in models of inflation and reheating process, without considering Dark Matter. Therefore, our unification scheme does not increase the number of parameters and it accomplishes the desired unification between the inflaton and Dark Matter for free.

TeV scale leptogenesis, inflaton dark matter, and neutrino mass in a scotogenic model

“…2 The possibility of a single field or particle playing the role of inflaton and DM was first pointed out in Refs. [38,39] and was taken up for detailed studies in several subsequent works [40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58].…”

An exceptional G(2) extension of the Standard Model from the correspondence with Cayley–Dickson algebras automorphism groups

“…For smaller interactions with the visible sector, the thermal production of DM particles is insignificant and DM must come from a non-thermal mechanism, leading to a Super-WIMP (SWIMP)-like scenario, for example through a direct DM-producing inflaton decay [148][149][150] , if the heavy Higgs scalar responsible for the G(2) → SU(3) transition is identified as the inflaton field. In this inflaton-portal case 151 , the glueball abundance is basically fixed by few parameters, i.e.…”

Supersymmetric ν-inflaton Dark Matter

“…[11], and different mechanisms to block the inflaton decay at late times after reheating the Universe were further studied in [12][13][14][15][16][17][18][19][20], the focus being in obtaining a remnant inflaton condensate as dark matter. But it was also soon realized that inflaton particles could be recreated later from the thermal bath and behave as a weakly interacting massive particle (WIMP), their abundance controlled by the standard freeze-out mechanism for dark matter [1,[21][22][23][24][25][26][27][28]; alternatively, for very weak couplings, it could also lead to a feebly interacting massive particle (FIMP) never coupled to the cosmic plasma, and the freeze-in mechanism for DM [29].…”