Is a Bell-type inequality for nondicotomic observables a good test of quantum mechanics

The possibility that a Bell-type inequality for nondicotomic observables, established previously (Baracco et al. Int. J. Theor. Phys.; 15:473 (1976)), can be a suitable tool for testing the prediction of quantum mechanics (Q.M.) concerning the correlations observable in a decay of an unpolarized particle of arbitrary spin into two massive particles is investigated. It is found that such correlations cannot violate the inequality for spins of the subsystems larger than 1/2 and it is suggested that, apart from the possibility of finding different sensitive observables, feasible and real tests of QM against local hidden variable theories will probably always imply photon processes, owing to the simplification introduced in the density matrix of the final state by the dicotomic nature of the photon spin variables. (author)