Flavor content of the nucleon in an unquenched quark model

TL;DR

This paper investigates the flavor composition of the nucleon using an unquenched quark model that explicitly includes quark-antiquark pairs, revealing an excess of anti-d quarks and significant orbital angular momentum contributions.

Contribution

It introduces an unquenched quark model explicitly accounting for quark-antiquark pairs, providing new insights into nucleon flavor asymmetry and spin structure.

Findings

Anti-d quark excess in the proton

Large orbital angular momentum contribution to proton spin

Explicit inclusion of quark-antiquark pairs in the model

Abstract

We discuss the flavor content of the nucleon in an unquenched quark model in which the effects of quark-antiquark pairs (up, down and strange) are taken into account in an explicit form. It is shown that the inclusion of quark-antiquark pairs leads to an excess of anti-d over anti-u quarks in the proton and to a large contribution of orbital angular momentum to the spin of the proton.