Meson-like Baryons and the Spin-Orbit Puzzle

TL;DR

This paper investigates meson-like b1_Q excited states, showing their spin-independent spectra resemble mesons and that small spin-orbit effects arise from a cancellation of forces, offering insights into the baryon spin-orbit puzzle.

Contribution

It introduces a class of b1_Q baryons with spectra similar to mesons and explains the small spin-orbit effects through force cancellations, addressing the spin-orbit puzzle.

Findings

Spin-independent spectra of b1_Q baryons resemble mesons.

Small spin-orbit effects result from force cancellations.

Provides a new perspective on spin-orbit forces in baryons.

Abstract

I describe a special class of meson-like \Lambda_Q excited states and present evidence supporting the similarity of their spin-independent spectra to those of mesons. I then examine spin-dependent forces in these baryons, showing that predicted effects of spin-orbit forces are small for them for the same reason they are small for the analogous mesons: a fortuitous cancellation between large spin-orbit forces due to one-gluon-exchange and equally large inverted spin-orbit forces due to Thomas precession in the confining potential. In addition to eliminating the baryon spin-orbit puzzle in these states, this solution provides a new perspective on spin-orbit forces in all baryons.