45 research outputs found
New features in curvaton model
We demonstrate novel features in the behavior of the second and third order
non-linearity parameters of the curvature perturbation, namely, and
, arising from non-linear motion of curvaton field. We investigate two
classes of potentials for the curvaton - the first has tiny oscillations
super-imposed upon the quadratic potential. The second is characterized by a
single 'feature' separating two quadratic regimes with different mass scales.
The feature may either be a bump or a flattening of the potential. In the case
of the oscillatory potential we find that as the width and height of
superimposed oscillations increase, both and deviate strongly
from their expected values from a quadratic potential. changes sign
from positive to negative as the oscillations in the potential become more
prominent. Hence, this model can be severely constrained by convincing evidence
from observations that is positive. , on the other hand,
acquires very large negative values. For the the single feature potential, we
find that and exhibit oscillatory behavior as a function of
the parameter that controls the feature.Comment: 1+14 pages, 5 figure