Constraining the anomalous coupling of gravitational waves with double pulsar

We revisit the decay of the orbital period in binary systems that occurs due to the emission of gravitational waves in the context of modified gravity models where the coupling $G_{gw}$ between matter and on-shell gravitons is allowed to differ from the Newton constant $G_N$. Using the most precise orbital parameters of binary pulsars, those of the Double Pulsar, we constrain the ratio $G_{gw}\mathrm{/}{G}_N$ to the level of ${10}^{-4}$, improving by two orders of magnitude the present bound on this quantity.