Tests for the Internal Quantum Numbers of Partons

The restrictions for the structure functions of deep-inelastic electroproduction and neutrino-induced production following from assigning partons to any representation of $\mathrm{SU}\mathrm{}\left(2\right)\mathrm{}\times \mathrm{SU}\mathrm{}\left(2\right)\mathrm{}\times Y$ are derived. Apart from the general parton-model assumptions only isospin invariance and positivity are used. Comparison with experiment allows us to exclude all models which have only partons of spin ½, isospin ≤½, and integral charge.