Chiral-odd transversity spin structure function h1( x) of the nucleon in a constituent quark model

Abstract

We study the chiral-odd transversity spin-dependent quark distribution function h 1( x) of the nucleon in a constituent quark model. The twist-2 structure functions, f 1( x), g 1( x) and h 1( x) are calculated within the diquark spectator approximation. Whereas an inequality f 1( x) > h 1( x) > g 1( x) holds with the interaction between quark and diquark being scalar, the axial-vector effective quark-diquark interaction, which contributes to the d-quark distribution, does not lead to such a simple relation. We find that h 1( x) for the d-quark becomes somewhat smaller than g 1 d ( x), when we fix the model parameter to reproduce known other structure functions. We also include corrections due to the non-trivial structure of the constituent quark, which is modeled by the Goldstone boson dressing. This improves agreements of f 1( x) and g 1( x) with experiments, and brings further reduction of h 1 d ( x) distribution. Consequences for semi-inclusive experiments are also discussed.