HIGHER-ORDER WEAK-INTERACTIONS AND THE EQUIVALENCE PRINCIPLE

We consider the possibility that gravity may couple anomalously to the weak interaction and thereby lead to a violation of the weak equivale nce principle. It is shown that the contribution to the energy of a nu cleus arising from neutrino-antineutrino exchange can be calculated ri gorously, and may be the dominant contribution from higher-order weak interactions. At the level of sensitivity that could be reached in the proposed STEP (satellite test of the equivalence principle) experimen t, detection of an acceleration difference between the test masses cou ld lead to new constraints on the coupling of gravity to neutrinos, an d to higher-order weak interactions.