Development of Hybrid Big Bang Nucleosynthesis with a primordial magnetic field

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K20927
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics; Astronomy
• Research Institution: Ibaraki University
• Principal Investigator: Yamazaki Dai 茨城大学, 全学教育機構, 准教授 (90531822)
• Research Collaborator: Kajino Toshitaka ; Kusakabe Motohiko ; Mathews Grant. J. ; Cheoun Myung-Ki
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 原初磁場 / ビッグバン元素合成 / 宇宙背景放射 / 大規模構造形成 / 弱レンズ効果

Outline of Final Research Achievements

(1) Using a model with the energy density of the primordial magnetic field (PMF) correctly, we can use relatively accurate observation data of angular scale larger than the galaxy clusters, and we can constrain the PMF more strongly.
(2) We find that the region in the power spectrum index of the PMF n_B < -1.5, where is dominated by linear perturbations, and the region in n_B > -1.5, which is dominated by the PMF energy density effects are not to be equivalent.
(3) To research with physical consistency, we promoted the program code for theoretical calculation of the big bang nucleosynthesis, the cosmic microwave background and matter density fields simultaneously for one parameter set, and to constrain the parameters.

Free Research Field

宇宙論

Academic Significance and Societal Importance of the Research Achievements

宇宙論及び天体物理学における磁場、ダークマターおよびビッグバン元素合成に起源をもつ軽元素の役割は多彩であり、宇宙全体の構造・天体形成・進化の研究方針を左右する重要な要素である。当研究により、原初磁場やダークマター候補のX粒子と光子冷却の理論研究を進め、ビッグバン元素合成を正しく再構築できれば、宇宙の構造や天体形成から我々の身の回りを形作る元素組成の決定にいたるまで、幅広い研究分野の発展に貢献できる。