Testing f(R) theories using the first time derivative of the orbital period of the binary pulsars

In this paper, we use one of the post-Keplerian parameters to obtain constraints on f (R) theories of gravity. Using the Minkowskian limit, we compute the prediction of f (R) theories on the first time derivative of the orbital period of a sample of binary stars, and we use our theoretical results to perform a comparison with the observed one. Selecting a sample of relativistic binary systems, we estimate the parameters of analytic f (R) gravity. We find that the theory is not ruled out if we consider only the double-neutron star systems, and in this case we can cover the existing gap between the general relativity prediction and the observed data.