Massless particles in a class of field theories (multispin Wave, Multimass Wave)

A unified description of elementary particles has long been sought that would eliminate the need to use a separate field for each particle and interaction. Such a theory not only must account for the multiplets, of massive particles known to exist, but also massless particles. Here we examine the inclusion of massless particles in the regular class of multimass, multispin wave equations. We present a general proof for the nonexistence of any such equation with mass spectra containing nondegenerate massless particles of higher spin