Bayesian Evidence for a cosmological constant using new high-redshift supernova data

We carry out a Bayesian model selection analysis of different dark energy parametrization s using the recent luminosity distance data of high-redshift supernovae from Riess et al. and from the new ESSENCE Supernova Survey. Including complementary cosmological data sets, we found substantial Evidence [Delta ln (E) similar to 1] against a time-varying dark energy equation-of-state parameter, and against phantom dark energy models. We find a small preference for a standard cosmological constant over accelerating non-phantom models where w is constant, but allowed to vary in the range - 1 to -0.33.