# Quark fragmentation as a probe of dynamical mass generation

## TL;DR

This paper introduces a gauge-invariant approach to studying quark propagation and hadronization, proposing a new method to experimentally probe dynamical mass generation in QCD through fragmentation functions.

## Contribution

It provides a gauge-invariant definition of the dressed quark mass and links it to fragmentation functions as an order parameter for chiral symmetry breaking.

## Key findings

- Defined a gauge-invariant quark mass using Wilson lines.
- Linked the interaction-dependent mass component to the twist-3 fragmentation function.
- Proposed an experimental method to probe dynamical mass generation in QCD.

## Abstract

We address the propagation and hadronization of a struck quark by studying the gauge invariance of the color-averaged cut quark propagator, and by relating this to the single inclusive quark fragmentation correlator by means of new sum rules. Using suitable Wilson lines, we provide a gauge-invariant definition for the mass of the color-averaged dressed quark and decompose this into the sum of a current and an interaction-dependent component. The latter, which we argue is an order parameter for dynamical chiral symmetry breaking, also appears in the sum rule for the twist-3 $\tilde{E}$ fragmentation function, providing a specific experimental way to probe the dynamical generation of mass in Quantum Chromo Dynamics.