12.00.00 Specific theories and interaction models; particle systematics
- 12.10.-g Unified field theories and models (see also 04.50.-h Higher-dimensional gravity and other theories of gravity-in general relativity and gravitation, 11.25.Mj Compactification and four-dimensional models)
- 12.15.-y Electroweak interactions; Extensions of gauge or Higgs sector, see 12.60.Cn or 12.60.Fr (1)
- 12.20.-m Quantum electrodynamics (10)
- 12.38.-t Quantum chromodynamics; Quarks, gluons, and QCD in nuclear reactions, see 24.85.+p (23)
- 12.39.-x Phenomenological quark models (6)
- 12.40.-y Other models for strong interactions (4)
- 12.60.-i Models beyond the standard model; Unified field theories and models, see 12.10.-g (1)
- 12.90.+b Miscellaneous theoretical ideas and models (restricted to new topics in section 12)