The quark orbital angular momentum of ground state octet baryons

TL;DR

This study investigates the quark orbital angular momentum in ground state octet baryons using an extended chiral constituent quark model, revealing significant orbital contributions and differences among baryons.

Contribution

It introduces a superposition of traditional and higher Fock state configurations to model baryon wave functions and estimates their coupling via the $^3P_{0}$ mechanism, fitting sea flavor asymmetry data.

Findings

Quark angular momentum ranges from 0.10 to 0.30 for various baryons.

Hyperons have slightly smaller quark angular momentum than the nucleon.

Orbital angular momentum accounts for up to 60% of the baryons' spin.

Abstract

Here we study the quark orbital angular momentum of the ground octet baryons employing an extended chiral constituent quark model, within which the baryon wave functions are taken to be superposition of the traditional $qqq$ and the $qqqq\bar{q}$ higher Fock components. Coupling between the two configurations is estimated using the $^3P_{0}$ quark-antiquark creation mechanism, and the corresponding coupling strength is determined by fitting the sea flavor asymmetry of the nucleon. The obtained numerical results show that the quark angular momentum of the nucleon, $\Sigma$, $\Lambda$ and $\Xi$ hyperons are in the range $0.10$-$0.30$. In addition, the quark angular momentum of all the hyperons are a little bit smaller than that of the nucleon. And the octet baryons spin fractions taken by the intrinsic quark orbital angular momentum could be up to $60\%$ in present model.