Diquark contributions to scaling violations and to σL/σT

Arguments for significant dynamical diquark substructure in baryons are reviewed. If present, integer-spin diquarks will absorb longitudinally polarized currents resulting in a relatively large value of R = σ_L/σ_T in certain kinematic regions of deep-inelastic reactions. We provide simple parametrizations for this higher-twist contribution to structure functions and to R. We present fits to the x and Q² dependences of SLAC-MIT data on electroproduction. Further tests are suggested, and implications are discussed for the interpretation of R in perturbative QCD.

Permanent address: Physics Department, University of Michigan, Ann Arbor, MI 48109, USA.