Baryon Magnetic Moments in a Relativistic Quark Model

TL;DR

This paper calculates baryon magnetic moments using a relativistic light-front quark model, showing improved fits to experimental data and reduced sensitivity to quark mass variations compared to nonrelativistic models.

Contribution

It introduces a relativistic framework with simple wavefunctions and nonzero quark anomalous moments, enhancing the accuracy of baryon magnetic moment predictions.

Findings

Good fit to experimental data without strange quark contributions

Relativistic effects cause about 20% variation in magnetic moments

Model predictions are less sensitive to quark mass choices

Abstract

Magnetic moments of baryons in the ground-state octet and decuplet are calculated in a light-front framework. We investigate the effects of quark mass variation both in the current operator and in the wavefunctions. A simple fit uses single oscillator wavefunctions for the baryons and allows the three flavors of quark to have nonzero anomalous magnetic moments. We find a good fit to the data without allowing for strange quark contributions to the nucleon moments. A slightly better fit is obtained by allowing for explicit SU(3)_f breaking in the wavefunctions through a simple mechanism. The predictions for magnetic moments in our relativistic model are also much less sensitive to the values chosen for the constituent quark masses than those of nonrelativistic models. Relativistic effects can be of order 20% in general, and can alter familiar relationships between the moments based on SU(3)_f and a nonrelativistic treatment of spin.