Fracture functions in the very forward limit

TL;DR

This paper discusses extended fracture functions in semi-inclusive DIS, highlighting their relation to composite operators in the forward limit and their potential to test target-independence of the proton spin effect.

Contribution

It introduces the concept of extended fracture functions and their identification with composite operator insertions in the forward limit, providing a new approach to study target-independence in proton spin phenomena.

Findings

Fracture functions can be linked to composite operators in the z -> 1 limit.

Polarised fracture functions can test target-independence hypotheses.

The approach offers a new theoretical framework for analyzing target fragmentation in DIS.

Abstract

This talk gives a brief discussion of extended fracture functions, which parametrise the non-perturbative physics in the target fragmentation region of semi-inclusive DIS. In the forward limit z -> 1, it can be seen that fracture functions can be identified with insertions of composite operators. This enables polarised fracture functions to be used to test a target-independence hypothesis of the ``proton spin effect''.