Search for sgoldstino in $e^{+}e^{-}$ collisions at $\sqrt{s}$ from 189 to 202 GeV with the DELPHI experiment

Recent theoretical studies have proposed new phenomenological scenarios where the gravitino is light and the sgoldstino can be light and so be detectable at LEP. A novelty of this framework is that the sgoldstino being a SM particle, its decay chains do not involve other supersymmetric particles, like the LSP (lightest supersymmetric particle), which could escape detection and lead to final states with missing energy. A search for sgoldstino has been performed, for the first time, in DELPHI. At LEP2 sgoldstinos are mainly produced accompanied by a photon. This process is followed by S decay into two gluons or two photons, leading to final states with three photons or two jets and one photon. Sgoldstino phenomenology, production mechanisms, the decay chains and the particle width, will be discussed. Since no evidence far this particle has been found, the limits on parameter space have been set. (4 refs)