NEW TESTS OF THE STRONG EQUIVALENCE PRINCIPLE USING BINARY-PULSAR DATA

One of the few experimental handles on the nonlinear properties of the gravitational interaction is to test the "strong equivalence principle," i.e., to test whether the ratio m(gravitational)/m(inertial) is 1 for self-gravitating bodies. We point out that existing observational data on the class of small-eccentricity long-orbital-period binary pulsars already provide a limit (namely \ m(g)/m(i) - 1 \ < 1.1 x 10(-2); 90% C.L.) which goes beyond corresponding solar-system limits in probing strong-gravitational-field effects. Possible observational ways of improving this limit are suggested.