Fermioners

Fermioners are a hypothetical class of elementary particles proposed within several beyond-the-Standard-Model frameworks. They are intended to be fermions, possessing half-integer spin and obeying the Pauli exclusion principle, but they carry an additional conserved quantum number—often called the fermioner charge or F-number—that distinguishes them from ordinary fermions.

Models invoking fermioners envision either elementary spin-1/2 particles or higher-spin states. They typically interact weakly with Standard Model fields and may couple to a new gauge boson or to hidden-sector mediators. In some constructions, fermioners arise as bound states of more fundamental constituents or as excitations of a hidden sector that communicates with ordinary matter through feeble portals.

Possible roles attributed to fermioners include candidates for dark matter if stabilized by the F-number, contributions to early-universe dynamics such as baryogenesis or neutrino mass mechanisms, and distinctive collider signatures with missing energy or displaced vertices.

Experimental evidence for fermioners has not been observed. Constraints from collider experiments, precision measurements, and cosmology depend on the specific model, but in general they require sufficiently large masses or very weak couplings.

See also: fermion, standard model, beyond the standard model, dark matter, hidden sector.