Eur. Phys. J. A (2016) 52: 160
https://doi.org/10.1140/epja/i2016-16160-8

Review

The parton orbital angular momentum: Status and prospects

¹ Department of Physics and Astronomy, University of Kentucky, 40506, Lexington, KY, USA
² SLAC National Accelerator Laboratory, Stanford University, 94025, Menlo Park, CA, USA
³ IFPA, AGO Department, Université de Liège, Sart-Tilman, 4000, Liège, Belgium

^* e-mail: liu@pa.uky.edu

Received: 4 August 2015
Accepted: 13 August 2015
Published online: 21 June 2016

Abstract

Theoretical progress on the formulation and classification of the quark and gluon orbital angular momenta (OAM) is reviewed. Their relation to parton distributions and open questions and puzzles are discussed. We give a status report on the lattice calculation of the parton kinetic and canonical OAM and point out several strategies to calculate the quark and gluon canonical OAM on the lattice.