EvoEMD: cosmic evolution with an early matter-dominated era

TL;DR

EvoEMD is a computational framework that models the evolution of cosmic relics during an early matter-dominated era, accounting for altered expansion rates and reheating effects, to study dark matter and leptogenesis scenarios.

Contribution

The paper introduces EvoEMD, a novel flexible tool for simulating cosmic relic evolution in universes with an early matter-dominated era, including decay and reheating effects.

Findings

Successfully models dark matter freeze-out and freeze-in.

Simulates leptogenesis in an early matter-dominated universe.

Provides a customizable platform for exploring new physics scenarios.

Abstract

We present EvoEMD, a framework to calculate the evolution of cosmic relics in a Universe with an early matter-dominated (EMD) era. There are mainly two aspects to consider in this regard. First, an EMD era changes the Hubble expansion rate with respect to the standard radiation-dominated (RD) universe. Second, when the EMD era ends, the out-of-equilibrium decay of the dominant matter component may reheat the thermal bath and dilute cosmic relics. We briefly introduce the cosmology with an EMD era, and present how it is implemented in the EvoEMD framework. Users can study the coupled evolution of different interacting species in an EMD or RD universe. Two important cosmic relics are dark matter and a net lepton number. In order to show the capabilities of EvoEMD, we include simple examples of dark matter produced via freeze-out and freeze-in, and also of leptogenesis. Moreover, users can modify the model files in order to explore different new physics scenarios. EvoEMD is hosted on Github at \url{https://github.com/ycwu1030/EvoEMD}.