ONLY PARTICLES WITH SPIN LESS-THAN-OR-EQUAL-TO 2 ARE MEDIATORS FOR FUNDAMENTAL-FORCES - WHY

According to modern physics, the mediators for all the fundamental for ces of nature have spin S less-than-or-equal-to 2: the photon for elec trodynamics (S = 1), gluons for strong interactions (S = 1), bosons fo r the weak force (S = 1), and gravitons for the gravitational force (S = 2). Why? We show that the demand that the equations of a fundamenta l field be consistent in the classical limit (when quantum effects are negligible, and the only sources of all the fields are classical poin t particles) leads to S less-than-or-equal-to 2. This consistency dema nd explains the above observation. This result also leads to a qualita tive conclusion that all the phenomena related to fields and particles of S > 2 are purely quantum effects, and thus their intensity is much smaller than that of fields and particles with S less-than-or-equal-t o 2. This explains why the most stable and widely spread elementary pa rticles are of S less-than-or-equal-to 2 and why, in spite of the theo retical possibility that the torsion field (of spin-3) can also be res ponsible for gravitation, it has not yet been experimentally observed.