“…States of the form (4) correspond to neutral states. Since the real spinor structure is appeared in the result of reduction C 2(k+r) → Cℓ p,q , then (as a consequence) a charge conjugation C (pseudoautomorphism A → A) for the algebras Cℓ p,q over the real number field F = R and quaternionic division ring K ≃ H (the types p − q ≡ 4, 6 (mod 8)) is reduced to particle-antiparticle interchange C ′ (see [24,25,26]). As is known, there exist two classes of neutral particles: 1) particles which have antiparticles, such as neutrons, neutrino 4 and so on; 2) particles which coincide with their antiparticles (for example, photons, π 0 -mesons and so on), that is, so-called truly neutral particles.…”