Role of gluons and the quark sea in the proton spin

TL;DR

This paper investigates how virtual gluons and the quark sea contribute to the proton's spin, providing theoretical constraints and comparing them with experimental data.

Contribution

It offers a new analysis of gluon and quark contributions to proton spin, including a general constraint on gluon effects and comparison with experiments.

Findings

Gluons and virtual quark-antiquark pairs significantly influence proton spin.

Derived a theoretical constraint on gluon contribution to proton spin.

Compared theoretical predictions with experimental measurements.

Abstract

The real, interacting elementary particle always consits of a 'bare' particle and a cloud of virtual particles mediating a self-interaction and/or the bond inside a composite object. In this letter we discuss the question of spin content of the virtual cloud in two different cases: electron and quark. Further, the quark spin is discussed in the context of proton spin, which is generated by the interplay of quarks and virtual gluons. We present a general constraint on the gluon contribution and make a comparison with the experimental data.