Single Spin Asymmetry in Inclusive Hadron Production in pp Scattering from Collins Mechanism

TL;DR

This paper investigates how the Collins mechanism contributes to single transverse spin asymmetries in inclusive hadron production during proton-proton collisions, using a transverse momentum dependent model.

Contribution

It introduces a model that incorporates transverse momentum dependence in fragmentation to evaluate the Collins mechanism's effect on spin asymmetries.

Findings

Asymmetry size matches RHIC experimental data

Model effectively captures azimuthal asymmetry in jet fragmentation

Supports Collins mechanism as a significant contributor to observed asymmetries

Abstract

We study the Collins mechanism contribution to the single transverse spin asymmetry in inclusive hadron production in pp scattering p^{\uparrow}p\to \pi X from the leading jet fragmentation. The azimuthal asymmetric distribution of hadron in the jet leads to a single spin asymmetry for the produced hadron in the Lab frame. The effect is evaluated in a transverse momentum dependent model that takes into account the transverse momentum dependence in the fragmentation process. We find the asymmetry is comparable in size to the experimental observation at RHIC at \sqrt{s}=200 GeV.