The gravitino is the spin- gauge field of local supersymmetry and the partner of the graviton. A massless four-dimensional gravitino has two physical helicities, ; a massive one has four, adding . The super-Higgs mechanism supplies these extra states from the goldstino.
Articles by others on the same topic
A gravitino is a hypothetical elementary particle in the framework of supersymmetry (SUSY), a theoretical extension of the Standard Model of particle physics. In SUSY, every fermion (matter particle) has a corresponding bosonic superpartner, and vice versa. The gravitino is the superpartner of the graviton, which is the proposed mediating particle of the gravitational force.