CONFORMAL 4TH-RANK GRAVITY, NONVANISHING COSMOLOGICAL CONSTANT AND ANISOTROPY

We show that the recently proposed conformally invariant model for the gravitational held, based on fourth-rank geometry, is equivalent, in vacuum, to general relativity with a nonvanishing cosmological constan t coupled to a Weyl vector field. Recent observational evidence sugges ts a non-vanishing cosmological constant and an essential anisotropy i n the large-scale structure of the universe, supporting our model. We also couple the model to matter in the low-energy regime where the con formal invariance has been broken.