Evolution of the Primordial Axial Charge across Cosmic Times

Area of Science:

• Particle Physics
• Cosmology
• Plasma Physics

Background:

• The axial charge in an electron-photon plasma is crucial for understanding early universe phenomena.
• Previous estimates of its decay rate were based on a naive theoretical approach.
• Accurate decay rates are essential for models of leptogenesis and cosmic magnetogenesis.

Purpose of the Study:

• To investigate the collisional decay rate of axial charge in an electron-photon plasma.
• To determine the temperature dependence of this decay rate.
• To compare the calculated decay rate with existing theoretical estimates.

Main Methods:

• Theoretical analysis of collisional decay processes.
• Calculation of decay rates in an electron-photon plasma.
• Consideration of high-temperature effects and infrared divergences.

Main Results:

• The decay rate of axial charge is proportional to the fine-structure constant (Γ_{flip}∝αm_{e}^{2}/T).
• This rate is orders of magnitude larger than previously estimated.
• High-temperature environmental effects regularize infrared divergences, leading to the enhanced decay rate.

Conclusions:

• The collisional decay of axial charge is significantly faster than predicted by naive estimates.
• This revised understanding has important implications for leptogenesis and cosmic magnetogenesis.
• Environmental effects in high-temperature plasmas play a critical role in particle physics phenomena.