The variation of the baryon-to-photon ratio during different cosmological epochs due to decay and annihilation of dark matter

17th Russian Youth Conference on Physics and Astronomy

物理学;天文学

Zavarygin, E.O.^1,2 ; Ivanchik, A.V.^1,2

Ioffe Institute, Polytekhnicheskaya 26, St.Petersburg

194021, Russia^1

St.Petersburg State Polytechnical University, Polytekhnicheskaya 29, St.Petersburg, Russia^2

关键词: Annihilation cross sections;    Big bang nucleosynthesis;    Cosmic microwave background radiation;    Dark matter;    Dark matter particles;    Gamma-ray background;    Observational data;    Photon ratio;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/661/1/012016/pdf
DOI  :  10.1088/1742-6596/661/1/012016

学科分类：天文学(综合)

来源: IOP

【 摘 要 】

An influence of annihilation and decay of the dark matter particles on the baryon-to-photon ratio has been studied for different cosmological epochs. We consider the different parameter values of the dark matter particles such as mass, annihilation cross section, lifetime and so on. The obtained results are compared with the data which come from the Big Bang nucleosynthesis calculation and from the analysis of the anisotropy of the cosmic microwave background radiation. It has been shown that the modern value of the dark matter density ΩCDM= 0.26 is enough to provide the variation of the baryon-to-photon ratio up to Δη/η ∼ 0.01÷1 for decay of the dark matter particles, but it also leads to an excess of the diffuse gamma ray background. We use the observational data on the diffuse gamma ray background in order to determine our constraints on the model of the dark matter particle decay and on the corresponding variation of the baryon-to-photon ratio: Δη/η10-5. It has been shown that the variation of the baryon-to-photon ratio caused by the annihilation of the dark matter particles is negligible during the cosmological epochs from Big Bang nucleosynthesis to the present epoch.