WEAK INTERACTIONS OF A LIGHT GRAVITINO - LOWER LIMIT ON THE GRAVITINO MASS FROM THE DECAY PSI-]GRAVITINO+ANTIPHOTINO

The massive gravitino of spontaneously-broken locally supersymmetric theories may well be very light, leading to a mixing between weak and gravitational interactions. Particularly interesting is the photon coupling to a gravitino-antiphotino pair, with a vertex factor (κ/m 3 2√6) γμq2: a one-photon exchange with ordinary fermions is equivalent to a local four-fermion interaction. From the upper limit on the decay ψ → gravitino + antiphotino we get a lower limit ∼ 10-8 eV/c2 on the gravitino mass. © 1979.