Spin-Orbit Dynamics from the Gluon Asymmetry

Determination of the orbital angular momentum of the proton is a difficult but important part of understanding fundamental structure. Insight can be gained from suitable models of the gluon asymmetry applied to the Jz = 1/2 sum rule. We have constrained the models of the asymmetry to gain possible scenarios for the angular momentum of the protons constituents. Results and phenomenology for determining Lz are presented. 1 Status of Proton Spin Structure For the past twenty years, much work has been done to understand the spin structure of the nucleons. There has been progress in determining the contribution of the lightest quarks to the spin, but there is still uncertain knowledge about the gluon contribution. Transversity studies have contributed additional insight about quark dynamics, but little is known about the the orbital angular momentum of the constituents.[1] This paper will summarize a project that provides a method of gaining insight into the nature of the orbital angular momentum of the nucleon constituents. ∗Talk given at the Spin Physics Symposium (DSPIN 2007), 3-9 September 2007, Dubna, Russia. Work supported by the USDOE Division of High Energy Physics, Contract DE-AC02-06CH11357. Email: [email protected]