Semi-inclusive \pi^\pm production - tests for independent fragmentation and for polarized quark densities

TL;DR

This paper demonstrates how semi-inclusive pion production measurements can test fragmentation assumptions and extract polarized quark densities without prior knowledge of parton distributions.

Contribution

It introduces a method to test independent fragmentation and determine polarized quark densities using semi-inclusive asymmetry measurements.

Findings

Validates the use of semi-inclusive asymmetries for testing fragmentation models

Provides a way to extract polarized strange and valence quark densities

Determines the ratio of specific fragmentation functions

Abstract

We show that measurements of semi-inclusive $\pi^\pm$ asymmetries on $p$ and $n$ with polarized and unpolarized target and beams allow, without any knowledge of the polarized parton densities 1) to test independent fragmentation and SU(2) symmetry for the polarized sea, and 2) to determine separately the polarized strange and valence quark densities, and the ratio of the fragmentation functions $D_s^{\pi^+ + \pi^-}/D_u^{\pi^+ +\pi^-}$