# Model Independent analysis of MeV scale dark matter: I. Cosmological constraints

## TL;DR

This paper develops a model-independent method to analyze MeV-scale dark matter's cosmological constraints, revealing that a large parameter space remains viable despite existing bounds.

## Contribution

It introduces a new methodology to determine effective couplings of MeV-scale dark matter to hadrons, enabling cosmological constraint analysis independent of specific models.

## Key findings

- Cosmological and astrophysical observations constrain some parameter space.
- A significant portion of MeV-scale dark matter parameter space remains viable.
- Methodology allows for model-independent analysis of light scalar dark matter.

## Abstract

Recent results from several direct detection experiments have imposed severe constraints on the multi-GeV mass window for various dark matter (DM) models. However, many of these experiments are not sensitive to MeV scale DM as the corresponding recoil energies are, largely, lower than the detector thresholds. We reexamine the light scalar DM in a model-independent approach. In this first of a two-part work, we develop an appropriate methodology to determine the effective coupling of such a DM to hadrons, thereby allowing for the determination of the corresponding annihilation rates. We find that while the parameter space can be constrained using cosmological and astrophysical observations, a significantly large fraction is still viable. In the companion paper, we study the sensitivity of both direct detection experiments as well as colliders to such a DM.