Finite temperature wave-function renormalization: A comparative analysis

We compare two competing theories regarding finite temperature wave-function corrections for the process H→e+e- and for n+ν→p+e- and related processes of interest for primordial nucleosynthesis. Although the two methods are distinct (as shown in H→e+e-) they yield the same finite temperature correction for all n→p and p→n processes. Both methods yield an increase in the He/H ratio of 0.01% due to finite temperature renormalization rather than a decrease of 0.16% as previously predicted. copyright 1997 The American Physical Society