Neutrino refractive effects during their decoupling era in the early universe

Abstract

There is an accepted approach to calculation of the neutrino flavor density-matrix in the halo of a supernova, in which neutrino amplitudes, not cross-sections, need to be followed carefully in the region above the region of frequent scatterings. The same reasoning and techniques, applied to the evolution of neutrino flavors and energy distributions in the early universe in the era of neutrino decoupling, leads to radical changes in the prediction of the effects of the neutrino-neutrino interaction. Predictions for the production of sterile neutrinos, should they exist, will also be changed.

Comments: The equations and fig. 1 are right, but there are big complexities in their solutions that make the general effects questionable for the moment, and make part of the commentary wrong as well