Why and how to make constituent and current quarks different

Abstract

In the absence of SU(6) W invariance breaking the symmetry generators, which classify hadronic states into degenerate SU(6) W multiplets, may be identified with the good components of observable local non-conserved currents integrated over a null plane (the light-like charges Q α , Q i α ), as is suggested by the free quark model. The breakdown of both SU(6) W and SU(3) invariance of the Hamiltonian requires the existence of a unitary transformation U ≠ 1, which distinguishes and relates the observable light-like charges Q α , Q i α and the symmetry operators W α , W i α , classifying the observed hadrons into mass non-degenerate SU(6) W multiplets. A general form of the transformation U is constructed in a broad class of quark field theories and it is then used to abstract from these theories new algebraic structures, which describe the effects of SU(6) W and SU(3) invariance breaking on certain observables. Some predictions valid in the invariance limit remain unaffected to all orders of SU(6) W and SU(3) invariance breaking ( D/F = 2 3 ratio for the isovector axial charges, relations between eN and νN inelastic scattering scaling functions, a few relations among magnetic moments, etc.), some are improved ( ΔS = 1 weak transitions, Δ-N-γM 1 transition) and some are completely removed ( g A = 3 5, μ N A = 0 etc.).