# Process dependence of the gluon Sivers function in inclusive $pp$ collisions: phenomenology

## TL;DR

This paper analyzes the process dependence of the gluon Sivers function in proton-proton collisions using a TMD scheme with initial- and final-state interactions, providing first constraints and predictions for various SSA observables.

## Contribution

It introduces a phenomenological analysis within a color gauge invariant model to constrain the gluon Sivers function and compares it with simpler models.

## Key findings

- First constraints on gluon Sivers functions from SSA data
- Predictions for SSAs in $J/9$ and photon production
- Comparison with generalized parton model results

## Abstract

Within the so-called color gauge invariant generalized parton model, a TMD scheme including initial- (ISI) and final-state (FSI) interactions, we present a phenomenological analysis of available SSA data for pion and $D$-meson production in $pp$ collisions. This allows us, for the first time, to put a preliminary constraint on the two universal types of gluon Sivers function entering the model. Predictions for SSAs in $J/\psi$ and direct photon production, as well as a comparison with the simpler generalized parton model (without ISIs and FSIs), are also presented.