# Production of Purely Gravitational Dark Matter: The Case of Fermion and Vector Boson

## TL;DR

This paper analyzes how purely gravitational interactions can produce fermionic and vector dark matter particles in the early universe, potentially explaining their relic abundance without other interactions.

## Contribution

It provides a comprehensive analysis of gravitational particle production for fermionic and vector dark matter, including heavy particles relative to the Hubble parameter.

## Key findings

- Particles lighter than the inflaton can be produced abundantly.
- Heavy particles above the Hubble scale can also be generated efficiently.
- Relic abundance depends on inflation scale and particle mass.

## Abstract

We consider the simplest possibility for a model of particle dark matter in which dark matter has only gravitational interaction with the standard model sector. Even in such a case, it is known that the gravitational particle production in an expanding universe may lead to a correct relic abundance depending on the inflation scale and the mass of dark matter particle. We provide a comprehensive and systematic analysis of the gravitational particle production of fermionic and vectorial dark matter, and emphasize that particles which are much heavier than the Hubble parameter but lighter than inflaton can also be produced abundantly.