Primordial Nucleosynthesis with a background magnetic field

Yudong Luo,Toshitaka Kajino,Motohiko Kusakabe,Michael A Famiano,C Spitaleri,L Lamia,R.G Pizzone,M La Cognata,S Romano

doi:10.1051/epjconf/202022702003

Abstract

We present our recent detailed calculation of the impacts from a background magnetic field on Big Bang Nucleosynthesis (BBN). Namely, the magnetic field impacts on the electron-positron thermodynamics, time temper-ature relation and the screening potential of the early Universe. Most interest-ingly, we investigated the electron-positron relativistic screening potential with the background magnetic field, such potential might lead to a non trivial effect on the electron capture reaction which could finally affect the neutron to proton ratio.

Highlights

In the standard big bang nucleosynthesis (BBN) model, the only free parameter is the baryonto-photon ratio (η), which is considered as a homogeneous quantity
Smaller scale of the primordial magnetic field (PMF) fluctuations inside the co-moving horizon is expected to survive during the BBN epoch [3]
It is possible to have sub-horizon PMF strength during neutrino decoupling epoch which can lead to an energy density inhomogeneity in the early Universe

Summary

Introduction

In the standard big bang nucleosynthesis (BBN) model, the only free parameter is the baryonto-photon ratio (η), which is considered as a homogeneous quantity. The previous study [2] introduced a constant scale invariant primordial magnetic field (PMF) strength within a co-moving radius 1 Mpc during the BBN epoch. Smaller scale of the PMF fluctuations inside the co-moving horizon is expected to survive during the BBN epoch [3].

Results

Conclusion