DEEP-INELASTIC STRUCTURE FUNCTIONS FOR BOUND-STATES IN THE LADDER APPROXIMATION

A simple relativistic expression for the structure function of a two-body S-wave bound state in λφ3 theory is obtained at all values of the scaling variable in terms of the Deser-Gilbert-Sudarshan-Ida spectral function of the Bethe-Salpeter wave function in the ladder approximation. A similar result is given for a fermionantifermion bound state with approximate wave function derived from conformal invariance. At small x the structure function has the expected peak broadened by the binding effect and for a fermion-antifermion S-wave bound state it behaves like (1-x)2 as x→1. © 1979 The American Physical Society.