Process dependent Sivers function and implications for single spin asymmetry in inclusive hadron production

TL;DR

This paper introduces a process-dependent Sivers function within the generalized parton model, revealing significant differences in predictions for single spin asymmetries in hadron production at RHIC energies.

Contribution

It incorporates process dependence of the Sivers function into the GPM, linking it with the collinear twist-3 approach and altering predictions for spin asymmetries.

Findings

Predictions for $$ and photon production differ from conventional GPM.

Process dependence leads to opposite asymmetry predictions.

Highlights importance of initial- and final-state interactions.

Abstract

We study the single transverse spin asymmetries in the single inclusive particle production within the framework of the generalized parton model (GPM). By carefully analyzing the initial- and final-state interactions, we include the process-dependence of the Sivers functions into the GPM formalism. The modified GPM formalism has a close connection with the collinear twist-3 approach. Within the new formalism, we make predictions for inclusive $\pi^0$ and direct photon productions at RHIC energies. We find the predictions are opposite to those in the conventional GPM approach.