Possible Exchange Degeneracy on the Light Cone
Abstract
The sum rule dξξ^{1}(F^{ep}_{2} F^{en}_{2})=13 and the stronger exchangedegeneracy relation F^{ep}_{2} F^{en}_{2}=16(F^{ν¯p}_{2} F^{νp}_{2}) between electron and neutrinoscattering (ΔS=0 transitions) structure functions are obtained in some versions of the quarkparton model. In this paper we identify the most general conditions under which the relations above are obtained both in parton models and in the formal lightcone algebra of quarkgluon field theories. In the lightcone approach the necessary condition is a support property for Fourier transforms of bilocaloperator matrix elements. The exchangedegeneracy relation is checked in perturbation theory for γ_{5} and γ_{μ} gluon models. A class of graphs which violates exchange degeneracy is identified, whose members all have exotic intermediate qq¯ states. These graphs are, in every order of perturbation theory, suppressed in the Bjorken limit by powers of q^{2} compared to the leading graphs. Therefore in such renormalizable theories exchange degeneracy is correct to leading q^{2} order.
 Publication:

Physical Review D
 Pub Date:
 May 1972
 DOI:
 10.1103/PhysRevD.5.2582
 Bibcode:
 1972PhRvD...5.2582F