  Finite-temperature and -density radiative corrections to the neutrino
effective potential in the otherwise CP-symmetric early Universe are considered
in the real-time approach of Thermal Field Theory. A consistent perturbation
theory endowed with the hard thermal loop resummation techniques developed by
Braaten and Pisarski is applied. Special attention is focused on the question
whether such corrections can generate any nonzero contribution to the
CP-symmetric part of the neutrino potential, if the contact approximation for
the W-propagator is used.
