Intrinsic quark transverse momentum in the nucleon from lattice QCD

¹  Institut für Theoretische Physik T39, Physik-Department der TU München - 85747 Garching, Germany, EU
²  Center for Theoretical Physics, Massachusetts Institute of Technology - Cambridge, MA 02139, USA
³  Institut für Theoretische Physik, Universität Regensburg - 93040 Regensburg, Germany, EU

Corresponding author: phaegler@ph.tum.de

Received: 14 October 2009
Accepted: 22 November 2009

Abstract

A better understanding of transverse momentum dependent quark distributions in a hadron is needed to interpret several experimentally observed large angular asymmetries and to clarify the fundamental role of gauge links in non-Abelian gauge theories. Based on manifestly non-local gauge-invariant quark operators we introduce process-independent distributions and study their properties in lattice QCD. We find that the longitudinal and transverse momentum dependence approximately factorize, in contrast to the behavior of generalized parton distributions. The resulting quark probability densities for the nucleon show characteristic dipole deformations due to correlations between intrinsic and the quark or nucleon spin. Our lattice calculations are based on mixed action propagators of the LHP Collaboration.