gravitinogoldstino

Gravinogoldstino is a term used in speculative or informal discussions to describe a gravitino–goldstino sector—either a bound state or an effective degree of freedom that embodies the mixing between the gravitino and the goldstino in theories where gravity and spontaneously broken supersymmetry coexist. It is not a standard elementary particle in the established literature.

Background and theory: In global supersymmetry, spontaneous breaking yields a massless fermion known as the goldstino. In local supersymmetry (supergravity), the goldstino is absorbed by the gravitino through the super-Higgs mechanism, giving the gravitino a mass. In many conventional formalisms, the goldstino’s degrees of freedom become part of the longitudinal polarization of the gravitino rather than a separate field. Some non-linear realizations of SUSY or certain effective field theory parametrizations retain language referencing a gravitino–goldstino system or use the compound term gravitinogoldstino to emphasize the association between these modes.

Properties and implications: If treated as a distinct object, a gravitino–goldstino would be a fermionic degree of freedom with interactions suppressed by the Planck scale and determined by the SUSY-breaking scale F, roughly m3/2 ∼ F/MPl in common conventions. Its phenomenology would overlap with gravitino scenarios, with implications for early-universe cosmology, gravitino production, and collider signatures featuring missing energy. However, in standard supergravity, no separate gravitinogoldstino particle is required beyond the gravitino and goldstino concepts, and the term is not widely used in mainstream theory.

See also: Gravitino, Goldstino, Supersymmetry, Super-Higgs mechanism, Constrained superfield, Non-linear SUSY.