Signatures of massive sgoldstinos at e+e- colliders

In supersymmetric extensions of the Standard Model with a very light gravitino, the effective theory at the weak scale should contain not only the goldstino G∼, but also its supersymmetric partners, the sgoldstinos. In the simplest case, the goldstino is a gauge-singlet and its superpartners are two neutral spin-0 particles, S and P. We study possible signals of massive sgoldstinos at e⁺e^- colliders, focusing on those that are most relevant at LEP energies. We show that the LEP constraints on e⁺e^-→γS (γP), ZS (ZP) or e⁺e^-S (e⁺e^-P), followed by S(P) decaying into two gluon jets, can lead to stringent combined bounds on the gravitino and sgoldstino masses.