Cosmology in delta-gravity

We present a model of the gravitational field based on two symmetric tensors. Gravity is affected by the new field, but if T-mu nu = 0, the predictions of the model coincide exactly with general relativity, so all classical tests are satisfied. We find that massive particles do not follow a geodesic, while massless particles trajectories are null geodesics of an effective metric. We study the cosmological case, where we obtain an accelerated expansion of the Universe without dark energy.