Electron-positron annihilation freeze-out in the early universe

  title={Electron-positron annihilation freeze-out in the early universe},
  author={Luke C. Thomas and Theodore Dezen and Evan B. Grohs and Chad T. Kishimoto},
  journal={Physical Review D},
Electron-positron annihilation largely occurs in local thermal and chemical equilibrium after the neutrinos fall out of thermal equilibrium and during the Big Bang Nucleosynthesis (BBN) epoch. The effects of this process are evident in BBN yields as well as the relativistic degrees of freedom. We self-consistently calculate the collision integral for electron-positron creation and annihilation using the Klein-Nishina amplitude and appropriate statistical factors for Fermi-blocking and Bose… 

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