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micrOMEGAs4.1: two dark matter candidates

G. Belanger, F. Boudjema, A. Pukhov, A. Semenov

TL;DR

The paper extends micrOMEGAs to handle two-component dark matter by generalizing Boltzmann evolution to include inter-sector interactions and semi-annihilation, enabling accurate relic density calculations for multi-component DM. It introduces numerical methods for stiff coupled differential equations and cross-section tabulation to improve performance, and defines a two-sector DM framework within discrete symmetries, including a Z4 example with a singlet and a doublet. The authors implement two-DM observables (relic density, direct and indirect detection) and provide user controls (fracCDM2, Beps) to account for inter-sector fractions. An illustrative Z4 model demonstrates two DM candidates and shows how conversions affect the abundances and signals. This work broadens the practical tools for multi-component DM phenomenology and multi-channel detection predictions.

Abstract

micrOMEGAs is a code to compute dark matter observables in generic extensions of the standard model. This version of micrOMEGAs includes a generalization of the Boltzmann equations to take into account the possibility of two dark matter candidates. The modification of the relic density calculation to include interactions between the two DM sectors as well as semi-annihilation is presented. Both DM signals in direct and indirect detection are computed as well. An extension of the standard model with two scalar doublets and a singlet is used as an example.

micrOMEGAs4.1: two dark matter candidates

TL;DR

The paper extends micrOMEGAs to handle two-component dark matter by generalizing Boltzmann evolution to include inter-sector interactions and semi-annihilation, enabling accurate relic density calculations for multi-component DM. It introduces numerical methods for stiff coupled differential equations and cross-section tabulation to improve performance, and defines a two-sector DM framework within discrete symmetries, including a Z4 example with a singlet and a doublet. The authors implement two-DM observables (relic density, direct and indirect detection) and provide user controls (fracCDM2, Beps) to account for inter-sector fractions. An illustrative Z4 model demonstrates two DM candidates and shows how conversions affect the abundances and signals. This work broadens the practical tools for multi-component DM phenomenology and multi-channel detection predictions.

Abstract

micrOMEGAs is a code to compute dark matter observables in generic extensions of the standard model. This version of micrOMEGAs includes a generalization of the Boltzmann equations to take into account the possibility of two dark matter candidates. The modification of the relic density calculation to include interactions between the two DM sectors as well as semi-annihilation is presented. Both DM signals in direct and indirect detection are computed as well. An extension of the standard model with two scalar doublets and a singlet is used as an example.

Paper Structure

This paper contains 7 sections, 15 equations, 1 figure, 3 tables.

Table of Contents

  1. Introduction
  2. Classification of 2-DM models.
  3. Relic density computation
  4. Evolution equations
  5. Solution of equations
  6. Two DM models in micrOMEGAs
  7. Example

Figures (1)

  • Figure 1: Abundance ($Y_i$) as a function of $x=M_{\rm CDM1}/T$ for each DM particle in the doublet and singlet $Z_4$ model when including all channels (full), only annihilation channels (dash), and also semi-annihilation channels (dot). Note that for CDM1 (left plot), adding semi-annihilation channels induces only a few percent variation in the abundance.