Signals of a superlight gravitino at hadron colliders when the other superparticles are heavy

If the gravitino is very light and all the other supersymmetric particles are above threshold, supersymmetry may still be found at colliders, by looking at processes with only gravitinos and ordinary particles in the final state. We compute here the cross sections for some distinctive signals at hadron colliders: photon plus missing energy, induced by , and jet plus missing energy, induced by and . From the present Tevatron data, we estimate the bound on the gravitino mass, corresponding to the bound √F > 335 GeV on the supersymmetry-breaking scale. We foresee that the upgraded Tevatron and the LHC will be sensitive to values of up to 4.9 × 10−5 eV and 1.2 × 10−3 eV, corresponding to √F up to 450 GeV and 2.2 TeV, respectively.