Target Fragmentation in Semi-Inclusive DIS: Fracture Functions, Cut Vertices and the OPE

TL;DR

This paper explores the theoretical framework of semi-inclusive DIS near the z -> 1 limit, analyzing fracture functions, cut vertices, and Green functions within the operator product expansion, with implications for spin physics.

Contribution

It establishes a connection between fracture functions, cut vertices, and Green functions in the OPE for semi-inclusive DIS, including explicit calculations in a simplified model.

Findings

Consistent relations between fracture functions and Green functions are derived.

Implications for target-independence of the proton spin effect are discussed.

Explicit (phi^3)_6 theory calculations support the theoretical analysis.

Abstract

We discuss semi-inclusive Deep Inelastic Scattering (DIS) in the z -> 1 limit, in particular the relationship between fracture functions, generalised cut vertices and Green functions of the composite operators arising in the OPE. The implications, in the spin-polarised case, for testing whether the "proton spin" effect is target-independent are explored. Explicit calculations in (phi^3)_6 theory are presented which are consistent with our observations.