New insight on the Sivers transverse momentum dependent distribution function

TL;DR

This paper presents a new extraction of the Sivers function, revealing the three-dimensional momentum structure of protons, using recent experimental data and exploring the role of sea quarks within a TMD framework.

Contribution

It introduces a novel extraction method for the Sivers distribution functions from recent SIDIS data, including an initial investigation of sea quark contributions.

Findings

Successful extraction of Sivers functions from HERMES and COMPASS data

Indications of sea quark influence on the Sivers distribution

Validation of the TMD factorization approach in this context

Abstract

Polarised Semi-Inclusive Deep Inelastic Scattering (SIDIS) processes allow to study Transverse Momentum Dependent partonic distributions (TMDs), which reveal a non trivial three dimensional internal structure of the hadrons in momentum space. One of the most representative of the TMDs is the so-called Sivers function that describes the distribution of unpolarized quarks inside a transversely polarized proton. We present a novel extraction of the Sivers distribution functions from the most recent experimental data of HERMES and COMPASS experiments. Using suitable parametrizations, within the TMD factorization scheme, and a simple fitting strategy, we also perform a preliminary exploration of the role of the proton sea quarks.