Cosmological Consequences of Exponential Gravity in Palatini Formalism

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We investigate cosmological consequences of a class of exponential f(R) gravity in the Palatini formalism. By using the current largest type Ia Supernova sample along with determinations of the cosmic expansion at intermediary and high-z we impose tight constraints on the model parameters. Differently from other f(R) models, we find solutions of transient acceleration, in which the large-scale modification of gravity will drive the Universe to a new decelerated era in the future. We also show that a viable cosmological history with the usual matter-dominated era followed by an accelerating phase is predicted for some intervals of model parameters.