Dark energy and the Boomerang data

The recent high-quality Boomerang data allow to test many competing cosmological models. Here I present a seven-parameter likelihood analysis of dark energy models with exponential potential and explicit coupling to dark matter. Such a model is conformally equivalent to a scalar field with non-minimal coupling to gravity. So far, the constraints on a dark energy - dark matter coupling were extremely weak. The Boomerang data constrain the dimensionless coupling $\beta$ to be smaller than 0.1, an order of magnitude better than previous limits. In terms of the constant $\xi$ of non-minimally coupled theories, this amounts to $\xi <0.01.$ On the other hand, Boomerang has not enough sensitivity to put constraints on the potential slope.