Test of Hybrid Metric-Palatini f(R)-Gravity in Binary Pulsars

We developed the parameterized post-Keplerian formalism for hybrid metric-Palatini f(R)-gravity. We obtained analytical expressions in the general eccentric case for four post-Keplerian parameters: $\dot{\omega }$, ${\dot{P}}_{\text{b}}$, r, and s. Using observational data of PSR J0737-3039 and PSR J1903+0327 we imposed restrictions on the parameters of hybrid f(R)-gravity and showed that this theory is not ruled out by the observations in strong field regime. In addition we obtained predictions for masses of systems components and found that considered astrophysical objects will be heavier than in GR.