  It is a known fact that a quintessence model with $w_q < -1$ fits the
publicly available Super Nova (SN) type Ia data better than a model with
cosmological constant or $w_q > -1$. Two types of models have this property:
Scalar fields with unconventional kinetic term and models with cosmological
constant and a slowly decaying Cold Dark Matter (CDM). In this work we
investigate the possibility of replacing the cosmological constant in the
latter models with gradual condensation of a scalar field produced during the
decay of the CDM and present some preliminary results. The advantage of this
class of models to the ordinary quintessence is that the evolution of the dark
energy and CDM are correlated and cosmological coincidence problem is solved or
at least reduced to the fine tuning of the coupling between decaying CDM and
quintessence field i.e the Hierarchy problem. Here we show that for part of the
parameter space these models are consistent with present estimation of
cosmological parameters.
