  In an inflationary cosmology, the observed primoridal density perturbation
could come from the quantum fluctuations of another light 'curvaton' field,
rather than the inflaton. In this case, it is essential that the curvaton
decays, converting its perturbation to an adiabatic perturbation. For the first
time, we consistently account for this decay in the simplest curvaton model
V(\sigma) = (m^2\sigma^2)/2 and point out that it gives rise to an important
logarithmic correction to the potential. Moreover, the potential will also
receive a correction from the thermal bath. As a consequence, the dynamics of
the curvaton are substantially altered compared to the original model in the
majority of the parameter space. It will therefore be necessary to re-calculate
all the predictions of the original model.
